Hold 1

Using numerical solver of single particle motions to probe plasma behavior
Asger Friis, s203886, Mikael Kim Tvermark Jensen, s213712, Nicolai Lomstein Jensen, s233622

Vejleder: Stefan Kragh Nielsen, DTU Fysik

Resume:
Magnetfelter bruges til at indeslutte plasma. Plasma bruges her til at skabe fusion. Fusion er en teknologi, der kan være en stabil energikilde i fremtiden. Således er det vigtigt at forstå, hvordan plasmaets partikler opfører sig i elektromagnetiske felter. Tidligere simuleringer udført af DTU Plasma Physics and Fusion Energy (PPFE) har vist visse resonansfænomener. Vi vil programmere en simulation af ladede partiklers opførsel, og sammenligne dette med kendte teoretiske resultater og med de tidligere simulerede fænomener. Yderligere vil vi, om muligt, sammenligne vores resultater fra simulationen med eksperimentelle resultater, med henblik på at få en bedre forståelse af virkelige fænomener.

Hold 1
Particle orbits in magnetized plasmas during large electric fields
Joshua Marquardt Andersen, Viggo Kongslev Hilbert
Vejleder: Stefan Kragh Nielsen; Lars Thor Sørensen, DTU Fysik
Resume:
The heating of plasma from large electric fields away from the cyclotron frequency is not well studied, and could potentially affect simulations of Tokamak fusion reactors. This kind of heating is usually assumed negligible, without good empirical evidence supporting the claim. It is therefore important to determine how well this appoximation holds, to ensure the accuracy of simulations. Futhermore we want to examine heating in Tokamak without neglecting this effect. 

Hold 2
Temperature calibration of MEMS hotplates
Alexander Eric Binning, Mathilde Broue Geilager, Victoria Kjems
Vejleder: Christian Danvad Damsgaard; Robert Steen Raunsgaard Jensen, DTU Fysik
Resume:
In the development of new sustainable and functional materials, it is crucial to have control over environmental parameters in the experimental setup, such as temperature, at an atomic scale to gather information on the materials’ structural properties at their realistic usage temperature. This can be achieved via MEMS hotplates that have accurate calibration and a minimal temperature gradient cross the hotplate. MEMS denotes Micro-Electronic-Mechanical Systems which consist of microelectronics and -sensors in the scale of 1-100 µm. With a wide application within research and materials sciences, hotplate MEMS-technology fits in between macroscopic technology and nanotechnology, and is therefore often a cost-effective and compact solution. In addition to a sensitive current control system, a MEMS hotplate can facilitate reactions in chemical systems. Additionally, when integrated with transmission electron microscopy (TEM), MEMS hotplates provide a platform for observing ongoing phase changes, crystal formations, diffusion  patterns and catalyst restructuring. In this project we characterize a double spiral MEMS hotplate, developed for use in microscopy. The purpose of the project is therefore to verify the quality and establish a reliable pre-calibration of the chips via optical analysis, SEM-EDS (energy-dispersion spectroscopy) and comparison to temperature readings from independent reference methods. The chips that have accurate readings can then be used in TEM experiments.

Hold 3
Numerical simulation of magnetic stray fields from topological spin textures
Jacob Søren Mærsk-Møller, Mikkel Schøler Sørensen
Vejleder: Felix Trier, Niklas Martin, DTU Energy
Resume:
Magnetic skyrmions are local whirl-like arrangements of the spin configuration that can behave like particles. Skyrmions can be created, moved and destroyed, with their sizes ranging between nanometers and micrometers, depending on the magnetic host material properties. Together with their topological nature, this gives them a wide variety of potential uses in the form of data storage and computing, and possibly even for energy storage. One way to experimentally observe magnetic skyrmions is with scanning NV (nitrogen vacancy) imaging. However, this technique measures the skyrmion’s stray field along the NV axis at a finite height above the magnetic surface, which makes the determination of the exact form of the underlying magnetic texture challenging. Therefore, with simulations of known spin configurations and their stray fields along the NV axis, it will be possible to correlate the experimental results with a given spin configuration There exist other magnetic imaging methods that could be applied to determine magnetic spin textures, like MOKE (Magneto-Optic Kerr Effect), XMCD (X-ray Magnetic Circular Dichroism) and MFM (Magnetic Force Microscopy). However, they have certain shortcomings such as: MOKE and MFM being primarily qualitative, MFM being invasive, MOKE and MFM having lower resolutions, and XMCD being less accessible.

Hold 4
Simulating turbulence in the NORTH tokamak
Albert Monne Breum, Daniel Ruchayskiy, Mikkel Blom Henrichsen
Vejleder: Alexander Simon Thrysøe, DTU Fysik
Resume:
Thermonuclear fusion energy is a sustainable energy source that presents a CO2-emission-free, baseload-capable alternative to fossil fuels. The fundamental principle of fusion energy is the nuclear reaction between light atomic nuclei. To achieve fusion, the particles must cross the Coulomb barrier, which in modern nuclear fusion, is commonly done by giving the particles more energy by heating them up. At particle energies needed to reach a sufficiently large cross-section, the particles are mostly, if not fully, ionized and thus in plasma state. Because the resulting charged particles are influenced by magnetic fields, magnetic confinement devices are used to confine the plasma. A common example of a magnetic confinement device, and the one we will be working with, is the tokamak. One of the biggest challenges in building a fusion energy power plant is reducing the energy losses due to turbulence in the plasma at the edge of a tokamak. The primary goal of this project is to better understand the mechanisms behind edge instabilities, which we will achieve by simulating the turbulence numerically. In principle, one could track every particle in the plasma and have a consistent system of equations, but the limited amount of computing power makes it impractical. Instead, different models to describe plasmas have been developed to model various effects. One such model is the ESEL model, which is derived from two-fluid theory with additional assumptions. The NORTH tokamak at DTU runs without a central solenoid, meaning that the poloidal component of the magnetic field is not present. This makes it susceptible to interchange instabilities, the same phenomena as the edge of a typical tokamak plasma. We will use experimental data from NORTH to evaluate the applicability and limitations of our simulation and the model.

Hold 5
MEMS pressure sensor for measuring inside the TEM
Filip Esper Wahlgren, Lara Nærby Pettersen, Mille Rye Aarup 
Vejleder: Christian Danvad Damsgaard, DTU Nanolab
Resume:
To observe live reactions of samples, one can do so in an electron microscope. When looking at reactions live in a gaseous atmosphere, the local pressure inside of the microscope needs to be known.  Pressure gauges are now used to estimate the pressure, sitting far away from the sample. By switching it out with a Pirani gauge, one could use the electronic signal to measure the pressure in the microscope. As a Pirani-gauge consists of a wire, that heats up when a current is sent through the MEMS-chip. That heat will be transferred to the gas molecules around it. When the pressure drops towards vacuum, the loss in particles makes it more difficult for the wire to dissipate heat. If the temperature is kept constant, the effect drops. Note that Pirani-gauge is sensitive to active gas flow, as it will read a higher pressure than the actual value. In our experiment, the gas in the chamber is considered stationary. By making a pressure sensor for inside the TEM, the MEMS pressure sensor will give scientists more precise measurements of pressure. Therefore, more precise information about a potential reaction can be recorded. For example, how gasses emerge or impact the process or sample. 

Hold 6
The investigation of the tumbling of folded paper strips in a windtunnel
Ellinor Victoria Grete Geertsen, Sune Posselt Vergmann, David Mathias Klausen
Vejleder: Kaare Hartvig Jensen, DTU Fysik
Resume:
This project is inspired by the daily phenomenon seen when papers tumble in the wind. When paper (especially when folded) is left on a plane outside, the wind will sometimes make it lift from the plane and make it move. Instead of simply flying, the paper may begin to tumble. The goal of this project is to examine the relations between the papers dimensions, folds, and wind tumbling, by recreating the phenomenon in a windtunnel.

Hold 7
Elektron og ionmodellering i NICE fusionsreaktor
Peter Hellerup Madsen, Uffe William Lind, William Klevang Eikholm
Vejleder: Stefan Kragh Nielsen, DTU Fysik
Resume:
Research into fusion as an energy source is interesting, as commercial fusion reactors have the potential for seemingly limitless carbon free energy. Fusion reactors work by forcing atoms to fuse together. The sun is massive enough to do this with gravity, but on earth we primarily use magnetic fields in order to magnetically confine the plasma. DTU will soon begin to build a tokamak-stellerator hybrid reactor called NICE and our simulations will be the preliminary tests of the machine and they can influence the design of the magnetic fields which will be used in the machine.

Hold 8
Fabrication and Characterization of Titanium Nitride Thin Films by Atomic layer deposition (ALD) and Sputtering
Nikolaj Fauerholt Jensen, Kristian Dam Petersen, Mattias Nolsøe Isaksen
Vejleder: Rafael Taboryski; Thomas Clausen, DTU Nanolab
Resume:
The continued development of the semiconductor industry and related electronic and optical technologies relies on advanced fabrication techniques. Cleanroom facilities enable the fabrication of nanoscale devices and thin films with controlled properties. Titanium nitride (TiN) is an interesting thin-film material due to its electrical, optical, and superconducting properties, as well as its compatibility with CMOS technology. Understanding how fabrication conditions influence the properties of TiN thin films is therefore essential for controlling their performance in potential applications.

Hold 9
Phase engineering of 2D materials for memory devices
Thomas Ek Udahl, Noah Birk Meisner
Vejleder: Manh-Ha Doan; Camilla Sørensen; Peter Bøggild, DTU Fysik
Resume:
Neuromorphic computing aims to develop computing architectures inspired by the how the brain processes and store information. 2D materials are promising candidates for these applications because some of them can exist in different crystal phases with distinct electronic properties. This project explores interfacial charge transfer as a route to phase engineering in 2D for nonvolatile memory. The central hypothesis is that contact with RuCl3 induces sufficient charge doping in Mo(1-x)WxTe2 alloys to promote a transition from the semiconducting 2H phase to a (semi)metallic 1T’-type phase. Combining Raman spectroscopy with electrical measurements will test this hypothesis and assess the potential of these van der Waals heterostructures for floating-gate memory.

Hold 10
Atomic moiré patterns - From playful AI models to full molecular dynamics
Alex Adrian Mirea, Mona Al-Kellaby
Vejleder: Peter Bøggild; Mads Brandbyge, DTU Fysik
Resume:
Moiré patterns appear when two 2D crystal lattices are placed on top of each other with a small difference in rotation angle or lattice constant. In bilayer graphene, this creates a larger-scale pattern determined by the relative positions of atoms in the two layers. Real 2D materials are not perfectly flat and may contain strain, wrinkles or blisters, which can locally change the atomic structure and affect the moiré pattern. The project starts from an interactive molecular dynamics model generated using AI, which will be examined, tested and developed further. 

Hold 11
Laser-induced phase change in TMDS
Frederik Gram, Nova Lund
Vejleder: Peter Bøggild; Pintu Singha; Camilla Holm Sørensen, DTU Fysik
Resume:
2D-materials are atomically thin crystalline materials consisting of a single or few atomic layers. Transition metal dichalcogenides, or TMDs, are a group of 2D-materials which attracts attention for their direct band gap, unique electron spin properties and polymorphic properties, meaning that they can exist in different crystal structures. MoTe2 and WTe2 are both examples of such polymorphs, that can exist in two structural phases, 2H and 1T’, with varying electronic properties between phases and depending on the number of layers. MoTe2 is semiconducting in its 2H phase and semi metallic in its 1T’ phase, and it has the lowest energy difference between the two phases of all the TMDs. WTe2 is semi metallic in its 2H phase and an insulator in its monolayer 1T’ crystal phase, where it is most stable, unlike most TMDs. The ability to change and control the phases of these materials brings possibilities for phase change applications, such as resistive switching, ideal for memristors for neuromorphic computing. By tuning the stoichiometry in alloys of MoTe2 and MoWTe2, Mo1−xWxTe2, the energy difference between the phases could possibly be minimized. The transition can be induced locally by laser annealing, and possibly reverted through electrostatic gating. The threshold laser power for the phase change depends on how much light the flake absorbs and how efficiently heat is conducted away, and thus on the number of layers, the substrate and the encapsulation. This project will explore laser annealing, and potentially electrostatic gating, as a means to measure how easily phase changes can be induced in MoWTe2 alloys of varying stoichiometries.

Hold 12
Materialisation of Stellarator Magnet Scaffolding
Lucas Iversen Novrup, Frederik Nygaard, Erik August Dam Østergaard 
Vejleder: Andrea Roberto Insigna; Riccardo Ragona; Søren Bang Korsholm, DTU Fysik
Resume:
Fusion energy offers a potential path to clean energy, but with one major caveat being the long term confinement of plasma. The stellarator is a promising magnetic confinement concept due to its inherently steady-state operation. However, stellarators are notoriously complex to design and construct, owing to their non-axisymmetric 3D magnetic fields in physical space. Devices like the Wendelstein 7-X at the Max Planck Institute in Germany make exclusive use of complex non-planar electromagnetic coils. An alternative is using a configuration of permanent magnets to shape the magnetic field lines. This project aims to design and 3D-print a scaffolding structure for a stellarator, enabling the precise placement of permanent magnets. To evaluate the resulting prototype, the generated magnetic field will be measured at key points and validated against numerical simulations provided by project supervisor Andrea Insinga in COMSOL.

Hold 13
Halvleder Nanolasere 
Storm Sønderskov Madsen, Yacqub Mahamed Aden
Vejleder: Jesper Mørk, DTU Electro
Resume:
Overførsel af information koster energi. Over lange afstande sker datatransmission via optisk kommunikation i fibre med ekstremt lavt tab. Inde i datacentre og på og mellem computerchips sendes information derimod stadig med elektriske strømme i metalledninger. Her er energitabet højt: Det koster typisk omkring 600 fJ pr. bit at sende data på en chip og op til omkring 5 pJ pr. bit mellem chips, mens en enkelt logisk operation kun koster få fJ. Over halvdelen af en chips strømforbrug kan stamme fra de elektriske forbindelser, og trafikken inde i datacentrene er flaskehalsen med op til 77 procent af datacentrenes strømforbrug1. Samtidig stiger energiforbruget til informationsteknologi hurtigt.
Optiske forbindelser har flere fordele sammenlignet med elektriske forbindelser. Fotoner kan transportere information med lavt energitab og uden de samme ohmske tab og opvarmning, som opstår i elektriske ledninger. Ved elektrisk signaloverførsel opstår der desuden tab på grund af modstanden i ledningerne, hvor en del af den tilførte energi omdannes til varme. Optisk signaloverførsel har ikke dette elektriske modstandstab, da informationen transporteres af fotoner i stedet for elektrisk strøm.
En optisk forbindelse kræver en lyskilde, der kan integreres på en chip. Her er halvleder-nanolasere en lovende kandidat. For at en laser kan fungere, kræves der grundlæggende tre ting: et aktivt materiale, en ekstern energikilde og en optisk resonator.
• Gain medium: et aktivt materiale, som kan forstærke lyset gennem stimuleret emission.
• Ekstern energikilde: der skal tilføres energi til det aktive materiale for at skabe en tilstrækkelig population af eksiterede elektroner.
• Optisk resonator: en struktur, der reflekterer fotoner frem og tilbage gennem det aktive materiale.
Når den optiske forstærkning i det aktive materiale bliver større end de samlede tab i resonatoren, kan laseren nå sin tærskel og begynde at udsende laserlys. I en fotonisk krystal-nanolasers er den optiske resonator realiseret af den fotoniske krystalstruktur, som kan indeslutte lyset i et meget lille volumen. Det gør det muligt at undersøge, hvordan resonatorens struktur og tab påvirker den nødvendige tærskel for laservirkning.

Hold 14
Effect of covering probe on non-linear decay in plasma
Mathias Lau Bohn-Hansen, Yilin Lu, James Wei Jie Ye
Vejleder: Riccardo Ragona, Stefan Kragh Nielsen, DTU Fysik
Resume:
A primary area of current research focuses on plasma’s role in energy generation. All natural energy on Earth originates from plasma fusion within the sun. Mimicking this process could provide a sustainable, clean and safe source of power. However, non linear wave interactions, resulting in parametric decay instabilities (PDI) within the plasma can cause significant energy loss by reducing heating efficiency. The objective of this project is to understand the frequencies driving this instability. A probe will be used to measure local electron density fluctuations. It is hypothesized that this decay is caused by interference near the probe itself, when this is inserted into the plasma. Covering the probe with a glass cap will be  investigated as a potential solution to this problem

Hold 15
Theory and simulation of particle handling in acoustofluidics
Allan Li, Sebastian Adrian Kornbech Larsen
Vejleder: Henrik Bruus, DTU Fysik
Resume:
Analysis of a wide range of particles, typically in size of nanometer to hundreds of micrometer, it is often a necessary step to separate families of particles from one another, isolate or mix certain ones. One of the aims in the field of acoustofluidics is the development of technologies that can do exactly that. The idea is to induce ultrasound waves that travel through microchannels containing a certain fluid of interest. As the ultrasound waves meet particles in the fluid, they exert what is known as the acoustic radiation force. They also induce acoustic streaming in the fluid, which then by Stokes drag affects the particles. The specifics of the waves and the channel can produce nodes of low pressure, towards which the particles can be pushed and gathered, thus making it possible to sort or mix fluids effectively. The major advantage of this technique is the lack of chemical alteration of the particles, which can be favourable in various biochemical research contexts. An example of application of acoustofluidics is separating cancer-cells from mediums that have different compressibilities, making it effective at detecting such diseases at early stages.

Hold 16
Atomic moire patterns 
Jakob Bolding Andreasen
Vejleder: Peter Bøggild, DTU Fysik
Resume:
My project on Atomic moire patterns, aims to create a digital tool so simulate molecular dynamics in layered two-dimensional materials, focusing on graphene. Understanding the forces of small changes between these molecular structures and their interactions, allows for discovery of new properties and qualities. A slight misalignment between two layers of graphene allows it to act as both a superconductor and an isolator, regulated by a gate voltage giving new ways to create nanoscale circuitry, as seen in literature 1. It also holds properties for mechanical nanostructures with its versatility and adhesive properties as seen in literature 2.

Hold 17
Stacking, fabrication, and characterization of semiconducting 2D materials
Christina Pedersen, Jonas Aarosiin Dahl
Vejleder: Peter Bøggild, Søren Raza, DTU Fysik
Resume:
The electrical properties of a material are largely dictated by the electrical band structure of the material. Consequently, by learning how to manipulate this band structure, it is possible to tailor and control the electrical and optical properties of a given material. Combining different conventional 3D materials has proven challenging due to strong chemical bonds. This motivates the concept of 2D materials, where only weaker forces dictate interlayer interaction. Studies have shown that exploiting the advantages of 2D materials in combination with stacking of the layers affects the electronic band structure of the material. Investigating how the band structure of semiconducting 2D materials, such as MoS2 and WS2, and exploring the methods for manipulating it is essential for developing next-generation electronic components. 

Hold 18
Investigating Corrosion Underneath Functional Coatings Using Terahertz Spectroscopy
Helena Olsson Jacobsen
Vejleder: Simon Jappe Lange; Jochen Dreyer;  Behnam Mohammadi, DTU Electro
Resume:
The shipping industry is a cornerstone of global infrastructure and economic activity, and its environmental footprint is under increasing pressure to improve. A large share of a vessel's fuel consumption is determined by the hydrodynamic condition of its hull, which in turn depends on the integrity of the protective coating applied to it. Assessing how well a coating is protecting the underlying metal from corrosion is therefore essential both for developing better coatings and for maintaining vessels in service. The most reliable assessment method, destructive analysis, requires removing the coating and is costly, slow and impractical at scale, which motivates the search for non-destructive testing (NDT) alternatives. Terahertz (THz) spectroscopy is a largely unexplored NDT candidate: most polymer-based coatings are transparent to THz radiation while the underlying metal reflects it, suggesting THz imaging could reveal corrosion and other defects without damaging the coating. This project investigates the feasibility and potential of THz imaging as an NDT method for detecting and monitoring corrosion beneath functional coatings, using destructive analysis as ground truth.

Hold 20
Hydrogen Rich Gas Storage in Gas Hydrates: The Effect of Material Confinement and Gas Mixture
Tobias Grøndal Jensen, Nicolas Baattrup-Andersen
Vejleder: Jyoti Shanker Pandey, Bhavikkumar Bhupendrabhai Mahant, DTU Kemi
Resume:
Hydrogen is a promising energy carrier in the green transition, but storing it safely and efficiently remains a challenge. Conventional methods such as compressed or liquid hydrogen storage, require either very high pressure or extremely low temperatures, making them costly and energy-intensive. Gas hydrates offer an alternative, as they can in principle store hydrogen under milder conditions. However, pure hydrogen hydrates only form under extreme conditions, so a gas mixture and thermodynamic/kinetic promoters are used to improve the formation conditions for practical hydrogen storage. The hydrate can further be formed within the pores of a nanoporous material (nanoconfine ment), improving formation conditions, allowing for more efficient hydrogen storage. This remains an active area of research, and in this project we investigate hydrogen storage in the porous material SBA-15, characterizing it and testing its performance in hydrate formation with a CH4/H2/propane gas mixture, to determine whether it is a suitable material for hydrogen storage. 

Hold 21
Designing a Lab-On-a-Chip to Measure Deoxygenation of Hemoglobin by Raman Spectroscopy
Timmy Bui, Nicklas Benigra Andersen
Vejleder: Lisa Bianca Barell, Anders Kristensen, DTU Health
Resume:
There is a need for quantification of oxygen delivery of red blood cells, e.g., for diagnostics of different diseases, and to study fetomaternal hemorrhage efficiently. Using Raman spectroscopy and microfluidics, a technique for measuring this oxygen delivery has been proposed. By focusing a laminar flow of blood, using 2 laminar flows of PBS, simulating a capillary, the oxygen delivery can be quantified using Raman spectroscopy; as the so-called Raman shift will differ for oxygenated red blood cells and deoxygenated red blood cells. As the type of hemoglobin a>ects the oxygen delivery, a higher concentration of fetal hemoglobin (HbF), than adult hemoglobin (HbA) will result in a higher oxygen delivery.

Hold 22
Optical and electrostatic gating modulation of the conducting interface between γ-Al2O3/SrTiO3
Philip Hjorth Christensen, Frederik Flintholm Lange
Vejleder: Felix Trier, Anshu Gupta, DTU Energy
Resume:
In a world of increasing demand for energy, due to the rapid growth in computing and AI, more energy efficient hardware will be essential for sustainable growth in the industry. Currently, nearly all of the worlds computing is done with bits, represented either by 0’s or 1’s, where every logic operation consumes some amount of energy in the femtojoule regime. Neuromorphic computing presents an alternative to this paradigm. Instead of using a huge number of transistors as logic gates, neuromorphic computing utilises memristors - memory resistors that can change their given resistances in a non-volatile fashion - to more efficiently store and process data. Some interfaces between oxides in so-called heterostructures, for instance the one between γ-Al2O3 and SrTiO3, has shown promising results that potentially can make them usable as memristors. The resistance in the interface has been shown to be non-volatile tunable to external stimuli such as light and electric fields. Therefore, it represents the overall aim of this project to examine the effects of external light and electric field stimuli on the oxide heterostructure comprised of γ-Al2O3 and SrTiO3.

Hold 1

Simulating charged particle drift in magnetically confined fusion plasmas

 Tobias Sejling Tops, Emily Bak Torp

Vejleder: Søren Bang Korsholm, Andrea Roberto Insinga, DTU Fysik

Resume:
In times with a constantly growing need for more sustainable energy, fusion energy is a promising solution. By heating up small atoms (generally isotopes of hydrogen) to temperatures above 100 million degrees, they can overcome the strong nuclear forces between them and collide, thereby fusing together. Furthermore, at these temperatures, the particles will ionize, and the individual charged particles can be manipulated, and thereby confined, by strong magnetic fields. Therefore the coil configurations creating the magnetic confinement of the plasma are crucial. And they still need to be optimized, to avoid the charged particles drifting, escaping the magnetic confinement, and colliding with the walls of the reactor, cooling down the plasma and decreasing the effectiveness of the fusion reaction. The goal of this project is to use COMSOL for simulating how charged particles drift in different magnetically confined plasmas, and see which configuration decreases the drift of the charged particles the most.

 

Hold 2

Characterization of Capacitive Micromachined Ultrasound  Transducers

Erik Vilain Thomsen, Tobias Lolk Knudsen

Vejleder: Søren Bang Korsholm, DTU Healthtech, Kitty Steenberg, DTU Nanolab

Resume:
Capacitive micro-machined ultrasonic transducers (CMUT’s) are used in ultrasound scanning as both an emitter and a detector. By delivering a current to the CMUT, the plate oscillates and produces a sound wave, and by exposing the circular plate to a sound wave, the plate oscillates and returns an electrical signal. The ability of the CMUT to emit and detect ultrasound waves depends heavily on the resonance frequency of the CMUT. To design and produce a CMUT is a timely and costly process, which means it is paramount to precisely determine the resonance frequency of the CMUT, so no design and production time is wasted on non-usable CMUT’s.

 

Hold 3

Quantum fiber

Ketil Bjørn Frankel, Marie harvig, Mikkel Nymand Gjaldbæk

Vejleder: Nika Akopian, DTU Electro

Resume:
The project aims to put a single photon source inside of a hollow core optical fiber in order to allow quantum comunication. The project must therefore learn how to identify an optimal single photon source. Which is from earlier research identified as: A InAsP quantum dot inside of a InP nanowire emitting a single wavelength and which has a short life time, which is important in order to maximize the possible information output of the system. The way these single-photon sources are created is by integrating a quantum dot into a nanowire waveguide consisting of semiconductors grown on a wafer, and inserting one of these into a hollow-core optical fiber. The method of insertion, which will be developed and iterated on throughout the project work, is to use a needle via a micro-controller to pick up and insert a nanowire into a fiber core. At the moment, it is only possible to place the nanowire outside the optical fiber. However, this will lead to loss of information, which is not optimal, since every single photon carries unique non-copyable quantum information, which is one of the main benefits of using quantum communication in the first place. This affords additional security and privacy through the no-cloning theorem. If the nanowire could be placed inside the fiber, the single photon source would send information directly inside this fiber, and there would be minimal loss. But placing the wire inside a fiber is a huge challenge. In order to achieve this reliably it will be necessary to experiment with different methods of placing the wire inside the fiber.

 

Hold 4

Bistable Nanomechanical Optical Memories

Sol Titus Tietgen Lillevang , Carl Johan Waldorff, Marie harvig, Christian Zilmer

Vejleder: Søren Stobbe, DTU Electro

Resume:
This project aims at designing and fabricating a nanomechanical bistable mechanism that works through electrostatic actuation. Bistable mechanisms are characterized by having two stable mechanical states. The ability to switch the bistable mechanism between the two stable states gives them use in programmable photonics as nonvolatile memory devices. These nonvolatile optical memories enables for use in programmable photonic computing, which has potential for doing matrix-vector multiplication at a lower energy consumption, thus aiding programs relying on linear-algebra such as graphics rendering, numerical simulations and neural networks.

 

Hold 5

Fabrication and characterization of MoSe2-based SPS

Rune Elbek, Christoffer Pold

Vejleder: Battulga Munkhbat, Pietro Metuh, Athanasios Paralikis, DTU Electro

Resume:
We are entering a quantum revolution, where single-photon sources (SPSs) play a central role in optical quantum computing, secure communication, and advanced cryptography. An ideal SPS must exhibit purity (one photon per excitation), efficiency (deterministic photon emission), and indistinguishability (photons have identical quantum mechanical properties). Traditional approaches such as attenuated lasers suffer from low efficiency, while solid-state emitters offer a more deterministic alternative. Among these, transition-metal dichalcogenides (TMDs) are attractive due to their simple fabrication, which is often done via the famous scotch-tape method, wavelength flexibility, strong excitonic effects, and easy integration with photonic structures. WSe2 has been widely studied for its single-photon emission near 750 nm, close to the Rb line at 780 nm. MoSe2, by contrast, emits around 800 nm, extending the spectral range toward telecom wavelengths (1300–1550 nm). It is also a direct bandgap material with demonstrated sub-nanosecond lifetimes, enabling faster single-photon emission, though research on MoSe2 remains less developed than on WSe2. To help advance the understanding of single-photon emission in MoSe2, this project focuses on developing key experimental and analytical skills related to fabrication, optical  characterization, and cryogenic measurement. These methods are essential for identifying and studying potential single-photon sources and for improving their performance.

 

Hold 6

Simulations of nanolasers using stochastic rate equations

Martin Alexander Nordahl Grytter, Serhat Gökcen

Vejleder: Jesper Mørk , Matias Bundgaard-Nielsen, DTU Electro

Resume:
For decades, microelectronics and communication systems have relied on metal wires to physically connect and transmit data (bits) between electrical components in a circuit. However, the rate and capacity that can be transmitted is greatly limited by the physical and thermal properties of the wires. With rising demand for more efficient, faster and bigger data transmission, interest in alternatives are growing. One such developing alternative is the usage of photons generated by nanolasers to transmit data over very very short distances. By modulating the current going into a nanolaser, which consists of photon emitters in an optical cavity, the lasers intensity can be used as a digital signal encoded with bit values, 0 or 1. However, due to these lasers being in the microscopic regime, quantum noise presents a hurdle when it comes to getting acceptable bit rates. In this project we try to develop the tools to understand the noise, and try to simulate and characterize a nanolaser and it’s noise.

 

Hold 7

NORTH, sammenligning af signaler eksperimentelt og simuleret

Karl Johan Falkesgaard Brendholdt, Sinus Drud Nielsen, Lukas Siekierski Glit-Jensen

Vejleder: Alexander Simon Thrysøe, Riccardo Ragona, DTU Physics

Resume:
In experiments on the NORTH tokamak, fluctuations at the kHz scale have been observed [Nielsen et al., 2021]. These fluctuations are believed to play a significant role in cross-field transport and edge plasma dynamics, but their physical origin is not fully understood. By applying simulations with synthetic diagnostics and directly comparing them to experimental data, we aim to gain deeper insight into the mechanisms driving these fluctuations. The project combines computational and experimental approaches and contributes to developing better tools for diagnosing and predicting turbulence-driven transport in fusion plasmas.

 

Hold 8

Liquid-core waveguides

Noah Lei Byrne, Jens Thomas Ravn Brink

Vejleder: Kristian Speranza Mølhave, DTU Nanolab, Philip Trøst Kristensen, DTU Electro

Resume:
It has been recognized that Silicon nitride nano-channels, filled with fluorescent liquids, show signs of demonstrating wave-guiding properties when illuminated under dark-field conditions. Originally developed for transmission electron microscopy, these lab-on-a-chip devices are now repurposed as liquid-core waveguides, introducing a new approach to optofluidic waveguiding at the microscale. To this end, the objectives of this project include recreating foundational experiments, simulating and modeling light propagation within nanofluidic channels, designing and integrating components on a fluorescence microscope, and conducting new experiments which quantify wave-guiding capabilities and performance. In essence, we ask the question; how good are these LCWGs at guiding light?

 

Hold 9

2D Stacking Materials

Mortaza Hasib Khedri, Oliver Benjamin Hansen

Vejleder: Timothy John Booth, DTU Physics

Resume:
The motivation of this project is to finish a automated 2d stacking machine. the machine should be able to rotate 2d materials and place 2d material, when combined it should be able to twist and stack 2d materials. The purpose of this machine being able to twist and stack them is for the study of twisttronics which is the study of how the properties of 2d materials change based on the angle between two layers, the changes in properties include change inducing superconductivity in the material and changing how it reacts to electricity, light, etc.

 

Hold 10

Quantum dot Fiber

Bertram Braa Ermose, Noah Skovsbo Ota

Vejleder: Nika Akopian, DTU Electro

Resume:
For quantum computers to effectively communicate with one another, one must transmit single photons as qubits between the different computers to transfer information. This type of communication is called quantum communication, and it’s the most secure method of communicating, because the no-cloning theorem ensures that it’s impossible to make a perfect clone of the data without destroying it and alerting the real receiver. This type of communication has, as of writing, been a challenge as most solutions either haven’t worked or haven’t achieved high enough efficiency for computers to communicate. To solve this problem, we aim at inserting a single photon source inside a fiber so all photons created will therefore be created within the fiber making it more efficient.

 

Hold 11

Friction and sliding of superlubric nanomaterials

Frederik Mast, Lukas Gustav Ernlund Simonsen

Vejleder: Peter Bøggild, Bjarke Sørensen Jessen, DTU Physics

Resume:
This project examines the twist-angle dependence of friction in bilayer graphene, where a moire pattern can lead to a state of extremely low friction known as superlubricity. We aim to directly probe this angular dependence by mechanically manipulating and rotating graphene flakes using an atomic force microscope (AFM), moving beyond traditional lateral force measurements. The research will be extended to explore graphene on complex oxide substrates like strontium titanate (SrTiO), where polar interactions may influence sliding. The combination of experiment and simulation will reveal how interfacial symmetry and lattice coupling govern superlubric motion. Understanding these mechanisms is crucial for fundamental tribology as well as for their role in quantum phenomena and potential applications in nanomechanics, such as creating tunable band gaps for more efficient solar cells.

 

Hold 12

Undersøge Casimir-effekten i bowtie-kaviteter

Thit Thomsen, Jens Præstegaard Nielsen

Vejleder: Søren Stobbe, Philip Trøst Kristensen, DTU Electro

Resume:
In this project we hope to design a latching system based on the Casimir effect and is a continuation of the work by Konstantinos Tsoukalas. The Casimir effect is a quantum effect arising from vacuum fluctuations of the electromagnetic field which often leads to breakage or stiction of the nanostructures in nano-electro-mechanical-systems (NEMS). In these systems the Casimir effect gives rise to strong, non-linear attractive forces. By utilizing the Casimir effect, we want to create a potential landscape that leads to a force on the cavity. Specifically, by arranging a set of parallel plates we can find the total force by applying the Proximity Force Approximation (PFA). When the cavity is perturbed, the frequency of the electromagnetic mode changes, which can be calculated from applying perturbation theory to Maxwell’s equations. Thus the system may function as a switch which only requires energy when transitioning between stable configurations. It could even work as a theoretical framework for fine measurements of the Casimir force in the future.

 

Hold 13

Numerical simulation of quantum light emission with a master equation approach

Mario Antonio Feldthus, Christian Terkel Ellgaard Nellemose

Vejleder: Luca Vannucci, DTU Electro

Resume:
Quantum light sources are essential for quantum communication and computing, with semiconductor quantum dots as strong candidates. Their properties, however, are influenced by host material interactions and phonons. Resonant excitation complicates distinguishing between the laser and emitted photons, so this project explores “super schemes” using two lasers for off-resonant excitation. Advanced numerical methods, such as the Finite Element Method, are used to calculate electron and hole states and predict their impact on photon emission. The aim is to gain deeper insight into quantum-dot light sources and support the development of practical quantum technologies.

 

Hold 14

Advanced Silicon Etching

Lukas Tóroddur Sass, Mikkel Cort Ehlers

Vejleder: Radu Malureanu, DTU Electro

Resume:
Silicon (Si) is the most used material for integrated circuits and, as such, there are extremely well-developed methods to manipulate it, including etching. By optimizing etching parameters, one can fabricate a wide variety of Si-based nanostructures, which can be used for different applications from optical circuits for telecommunication to biosensors. However, new optical structures need advanced etching procedures.

 

Hold 15

Investigating the effects of beam tunnel dimensions on microwave beams in DEMO

Luna Bilgrav, Dines Peter Fink Kjeldgaard

Vejleder: Søren Bang Korsholm, Jesper Rasmussen, Théo Verdier, DTU Physics

Resume:
Our project has to do with fusion, which has potential to supply the world with sustainable energy. A lot of research around the whole world is being done and the culmination of this has been the creation of ITER. Now, the planning of ITER’s successor is in the works: DEMO. This construction is supposed to be able to create a surplus of energy. In ITER, DTU contributed with a collective Thomson scattering (CTS) diagnostic. This does measurements of the plasma by directing a microwave beam into the plasma and then measuring the effects on the ion dynamics. DTU is currently making a feasibility study on such a diagnostic system in DEMO. Our main objective is to measure the effect of the dimensions of the aperture and tunnel in which microwaves are being sent through.

 

Hold 16

Fabrication of on-chip photonic devices

Magnus Debes, Silas Wang

Vejleder: Pietro Metuh, Battulga Munkhbat, DTU Electro

Resume:
There are many ways to encode quantum information for use in quantum computing. One approach is based on photonic systems, one of the ways to do this is by encoding the information into the polarization state of single photons. In this scheme, single-photon sources generate the quantum bits (qubits), and optical components such as waveguides, beam splitters, and interferometers are used to manipulate and process the encoded information. Traditionally, these photonic circuits have been realized using silicon (Si) or silicon nitride (SiN) platforms, owing to their compatibility with existing semiconductor fabrication processes and their relatively low optical losses. In recent years, however, two-dimensional (2D) materials, particularly transition metal dichalcogenides (TMDs) have emerged as highly promising candidates for next-generation photonic quantum technologies. These materials offer a unique combination of properties that are highly advantageous for quantum photonics. For example, tungsten desulfide (WS2) possess exceptionally high refractive indices and strong optical anisotropy, enabling efficient light confinement and manipulation at the nanoscale.

 

Hold 17

Udvikling af Hall-effekt sensor til kontaktløs strømovervågning i laserstrømforsyning til rumfartøjer

Christin Holm, Frederik Bjerre Dansbo

Vejleder: Rafael Taboryski, DTU Nanolab

Resume:
This project builds upon a previous master thesis in which a custom-designed Hall-bar chip was developed and fabricated. The device is part of the ongoing effort to create a compact, galvanically isolated current sensing solution for the LISA (Laser Interferometer Space Antenna) mission – a space-based gravitational wave observatory. In LISA, laser interferometry is used to measure distance variations with picometer precision to ensure theses variations indeed is caused by gravitational waves, and not fluctuations in the spacecraft’s power systems or magnetic fields, housekeeping sensors are required. One of these is the Hall-bar sensor, which measures the magnetic field generated by the current in the power supply. The Hall-bar sensor is based on the Hall effect, in which charge carriers moving through a conductor experience the Lorentz force when exposed to a perpendicular magnetic field, producing a measurable transverse voltage. This voltage can be used to determine the magnetic field strength and thereby the current flowing through the system. The goal of this project is to characterize and optimize the performance of the Hall-bar chip through experimental measurements, bonding, and electrical characterization. A key focus is to minimize thermal drift. A challenge identified in previous prototypes. The overall aim is to validate the device’s suitability for the LISA mission.

 

Hold 18

Wet etching for patterning atomically-thin superconductors

Jonathan Schack-Lindhardt, Berhan Bayda

Vejleder: Battulga Munkhbat, Pietro Metuh, DTU Electro

Resume:
Detecting single photons is essential in the development of quantum optics and technologies, as without the ability to distinguish individual photons, light behaves classically. Quantum technologies, such as qubits encoded in the properties of single photons, rely on this distinguishability to exploit non-classical effects. Superconducting nanowire single-photon detectors (SNSPDs) are a class of photon detectors with clear advantages over other types of photon detectors. The SNSPDs have a high detection efficiency, low timing jitter and low recovery time. The main motivation for this project is to characterize the nanofabrication process for a niobium diselenide (NbSe2) based chip used in SNSPDs. The research group whom we work with is focusing on producing superconducting nanowires from thin flakes of NbSe2, whose layered structure is stabilized by strong in-plane covalent bonds and weak interlayer van der Waals forces. This anisotropy makes it particularly suitable for patterning, as etching can remove entire layers vertically without significantly damaging the sidewalls defined by the mask. In comparison to fabrication of regular SNSPDs, which require complex and precise fabrication techniques, the NbSe2 based SNSPD is easier to exfoliate, pattern and integrate with photonic circuits, simplifying the fabrication process. Our objective is to etch the thin flakes of NbSe2 and thereby characterize the behavior of the etching process on the material. The nanofabrication processes we will be exploring in this project involve the exfoliation and transferring of NbSe2 to produce a near 2D material. Using the wet-etching technique to remove layers on the sample and observing multiple parameters we aim characterize and understand the processes in detail. The parameters we will be observing is the temperature, solution ratio, and etching time.

 

Hold 20

Visualization, analysis and interpretation of XFEL data on the Fe(CN)₆^4- ligand substitution reaction

Max Rufus Schepelern Karrebæk, Jonas Mørk Maegaar

Vejleder: Kristoffer Haldrup, DTU Physics

Resume:
The project aims to explore the structural dynamics of the intermediate species in the photoaquation of iron(II)hexacyanide (Fe(CN)₆^4-). We will conduct a model independent analysis ie. a singular value decomposition (SVD) and use results from molecular dynamics (MD). The data have been collected at the SACLA XFEL by photoexciting a 200 mMol aqueous solution of Fe(CN)₆^4-using a 330 nm UV 30 fs laser pump pulse and probing with an 18 keV 50 fs x-ray pulse in a He atmosphere yielding a 0.5 ps temporal resolution. The analysed signal is the difference between x-ray scattering with and without the UV laser. Transition metal complexes play important roles in many biological and technological processes. Iron complexes are of particular interest as iron is cheap and abundant. One readily available complex is Fe(CN)₆^4-. Although not of particular interest in its applicability alone, it is easily obtained and well studied using spectroscopic methods. Still, while the overall reaction is reasonably well understood, a few questions still remain: What are the structures of the intermediate species of the reaction, and what is the cause of the relatively long ∼20 ps time scale for the aquation of the intermediate iron(II)pentacyanide? In this project, we will utilize ultrafast Time-Resolved X-ray Scattering (TR-XS) to investigate the structural changes in intermediate species during photoaquation of Fe(CN)₆^4-on a ∼5 picosecond time scale with sub-picosecond data. This enables us to go directly from ultrafast structural data to molecular dynamics, in contrast to recent studies. Specifically, we aim to investigate the long time scale for the aquation. This knowledge could potentially be used to explain fundamental solvent dynamics and utilised in biological and technological applications.

 

Hold 24

Measuring acoustic impedance and absorption with the impedance tube

Toke Kollenberg Aaris Agensø, Sofie Zhang Larsen, Ieva Stonciute

Vejleder: Jonas Brunskog, Frieder Lucklum DTU Electro

Resume:

The impedance tube method is a way to measure and characterize the acoustic properties of materials such as impedance and absorption. These properties of materials are important for various fields of acoustics such as noise control, product design, architecture, industrial design, transportation vehicle design, etc. For non-rigid materials, discrepancies may arise due to changes in the sample length during mounting. These discrepancies affect the estimated acoustic properties of the material. For this reason, we are interested in researching these discrepancies, and how they fit in the model.

Hold 25

Theory of optical modes in a nanostructure with nontrivial shape

Daniel Ejholm Skovlyst, Tobias Elholm

Vejleder: Yi Yu, Dayang Li, DTU Electro

Resume:
The increase in demand of computational power has led to limits in conventional electronic components and interest in optical solutions is surging. A promising solution lies in optical computation and optical integrated circuits. In particular, optical resonators are the cornerstones of optical integrated circuits. In order for this component to be integrable in established electronic circuit frameworks its size has to be comparable to that of modern components, preferably close to that of a transistor. This reduced size requirements of the resonator has led to the need for a redesign. The key factor of determining the usefulness of a resonator is the so called quality factor (Q-factor) as a measure of confinement time. For resonators at this scale, it becomes increasingly difficult to sustain high Q-factors by conventional means, but certain geometries offer a solution in the form of bound-state in the continuum modes (BIC modes). BICs can ensure high Q-factors on sub-wavelength scales where conventional methods fail. In this project, we will focus particularly on elliptical-shaped dielectric resonators, as they have been shown to host BICs while their mode properties,  compared to other primitive shapes, remain less explored.

Hold 1

Etching of hafnium disulfide for optical applications

Jens Westermann Rasmussen (s234416), Frederik Martin Felding (s225135)

Vejleder: Søren Raza, Peter Bøggild, DTU Fysik

Resume:

Hafnium disulfide (HfS2) is a novel van der Waals material with a high refractive index in the visible spectrum. This property could make HfS2 a viable candidate for fabricating nano-optics, e.g. flat metasurfaces or thin waveguides. However, to unlock this potential, an optimised etching process is needed, as current purely physical sputtering processes result in rough sample topologies. In this project, we seek to develop a dry-etch process which also uses chemical reactions between the gas and HfS2, instead of the current processes.

 

Hold 2

Automated characterization and analysis of next-generation solar cell materials

Sara Corfixsen Milthers (s224057), Selma Lien (s224069)

Vejleder: Lena Mittmann, Andrea Crovetto, DTU Nanolab

Resume:

Most of our energy today comes from fossil fuels. This is both unsustainable and damaging to the environment. Therefore, it is crucial that we convert to renewable energy sources, such as solar power. To optimize both the production of solar cell materials and the photovoltaic (PV)conversion efficiency of thin-film solar cells, phosphosulfate materials are being characterized with solar cell application in mind. Thin-film solar cells have a reduced material usage and lower cost of manufacturing compared to traditional crystalline silicon solar cells. Additionally, Phosphorusand sulfur are abundant elements on our planet, making out respectively 0.1% and 0.05% of the Earth’s crust. A way of analyzing a new material is by using Energy-dispersive X-ray spectroscopy (EDX). The characteristic X-rays are used to determine the elements that the material consists of. For the characterization of the new phosphosulfide materials, the thicknesses of the thin-films are required. The depth analysis conducted by the EDX is based on the ratio of characteristic X-rays from silicon, the wafer substrate material, and the phosphosulfide components. To validate the EDX depth analysis, cross-section images of wafers are measured directly using ImageJ. The cross-sections images are obtained with a Scanning Electron Microscope (SEM) to achieve high magnification and resolution. Creating phosphosulfide solar cells that reach a high-level of efficiency nearing the Shockley–Queisser limit could be a cost-effective solution to the energy crisis we are facing today.

 

Hold 3

Determination of the Debye length by simulation of plasma

Elias Lindegaard Andersen(s234459), Peter Nonbo Messerschmidt(s234455)

Vejleder: Anders Henry Nielsen, DTU Fysik

Resume:

A plasma is a hot collection of free electrons and ions, showing collective neutral charge over certain volumes and length scales (Debye length). This neutrality is also referred to as quasi-neutrality. Plasmas are everywhere around us, and with the urgent need for green energy like fusion power, understanding how plasmas behave is more relevant than ever. A fundamental property of plasmas is the Debye length, which can be interpreted as the length scale at which a plasma acts electrically neutral. For the plasma physics course, no. 10400, a teaching tool is needed to help students visualize how the Debyelength determines the way a plasma acts. The goal of this project is therefore to test whether simulating a plasma in a simple one-dimensional case, can predict the Debye length, and to refine the simulation such that it can be used as teaching material for the plasma physics course no. 10400.

 

Hold 4

Spatial resistance mapping of γ-Al2O3/SrTiO3 2DEGs

Stig Asbjørn Tscherning Jønsson (s234456), Emil Nymann Lund Madsen(s234426)

Vejleder: Felix Trier, Thor Hvid-Olsen, DTU Energy

Resume:

Kortlægning af resistansen i oxidholdige materialer er afgørende, da disse materialer ofte udviser komplekse og lokalt varierende elektriske egenskaber. Ved at undersøge resistansen kan man få indsigt i, hvordan struktur, sammensætning og defekter påvirker elektrisk ledningsevne. Dette er essentielt forat designe og optimere materialer til specifikke applikationer, hvor oxiders unikke egenskaber kan udnyttes. En vigtig komponent i denne forskning er 2DEG (to-dimensionel elektron gas), som dannes i grænsefladen mellem blandt andet γ − Al2O3 og SrTiO3. Denne struktur muliggør studier af elektriske egenskaber på nanoskala og kan ændre ledningsevnen med flere størrelsesordener under påvirkning af et elektrisk felt. Denne indsigt kan føre til udvikling af spintronik og spin-resistorer, som potentielt kan være mere energieffektive og kompakte end traditionelle transistorer

 

Hold 5

Numerical simulation of quantum dots with the Finite Element solver

Alex Larsen(s234030), Daniál Rasmussen(s234443)

Vejleder: Luca Vanucci, DTU Electro

Resume:

Near-future optical quantum technologies will increase the need for more sophisticated and engineered solutions using quantum light sources. Most quantum light sources are based on confining an electron-hole pair inside a semiconductor quantum dot which allows precise control of the wavelengths emitted by trapped particles upon electron-hole recombination. Therefore it is important to investigate the quantum mechanical behaviour of electrons and holes trapped in semiconductor quantum dots using appropriate simulation software.

 

Hold 6

Two phase flow and droplet generation in nanochannels

Thomas Møller Damm(s234423), Mathias Skovsbøl Andersen(s234421)

Vejleder: Kristian Speranza Mølhave, Mervan Ramadan, DTU Nanolab

Resume:

Microscale droplet generators are essential in studying interactions between different fluids at nanoscale as the high surface to volume ratio gives high reaction rates. Furthermore, lab-on-a-chip technologies as well as chemical and biological analysis use microscale droplet generators both to get a higher resolution analysis (determined by the amount of analyte per droplet) as well as saving on the amount of analyte used (determined by the volume of the droplet). Microscale droplets also allow multiple processes simultaneously with equal starting conditions, which is useful in e.g. cell mutation analyses. All of the above benefits of using microscale droplets only increase with smaller droplets, and nanoscale droplet generators capable of generating droplets consistently are therefore of interest. Previously, nanodroplets have been hard to generate, but with recent breakthroughs in nanochannel manufacturing, traditional microdroplet generation methods, using microchannels, can possibly be used. However, with a shorter scale, the ratio of surface area to volume will increase. Therefore, surface tensions will dominate the hydrodynamics to a higher degree, and investigating nanoscale droplet generating techniques is of interest.

 

Hold 7

To explore the feasibility of 3D imaging for characterising the input and output material for a CO2 mineralisation reactor

Erik Pagh Goodwin (s234461), Maria Murmann Løhndorf(s234436)

Vejleder: Susan Louise Svane Stipp, DTU Fysik

Resume:

The amount of CO2 in our atmosphere concerns society and methods to capture CO2 are being developed. A group of scientists at DTU Physics is currently researching CO2 mineralisation, where the goal is to combine waste building material with CO2, to produce a new building material. The waste materials are e.g. concrete and stone wool, which are commonly used materials in the building industry. In perspective to making a new building material with CO2, the opportunity to make a more environmentally friendly, cheap concrete additive is also being studied by the same group of scientists. This is done by characterising materials. For our project this includes diatoms, a microplanktonic algae that cover their single cells with glass structures and hold a secret for producing amorphous colloidal silica, and waste building materials concrete and stonewool before and after reaction in a CO2 trap reactor.

 

Hold 8

Characterizing an FPGA-based digitizer for fusion plasma measurements

Victor Henrik Oliver Havrehed(s234427), Tobias Peter Elholm(s234431)

Vejleder: Jesper Rasmussen, Kenneth Thranekjer Petersen, DTU Fysik

Resume:

When working with fusion energy, it is necessary to measure the properties of the plasma where the fusion processes take place. A way this is done is by injecting different wavelengths into the plasma, and receiving the scattered waves with a digitizer. For this project, the focus is microwaves, used for CTS (Collective Thompson Scattering)measurements of fusion plasmas. CTS measurements return an Intensity vs. Frequency spectrum, used to measure plasma characteristics, such as ion velocity distribution. Current digitizers have 8 bit resolution, a short sampling period, and are prone to data clogging. The digitizer in this project is 12 bit, and will analyse plasma properties in real time, with a longer sampling period. A higher resolution CTS frequency spectrum will be measured, improving on velocity distributions and temperature measurements throughout an entire plasma discharge. Before a faster FPGA (Field Programmable Gate Array), which is connected to the digitizer can be used, it needs to be calibrated in order to show accurate and precise data. The calibrated digitizer will be tested using plasmas measurements from DTU’s NORTH tokamak. The final destination of this FPGA will be the ASDEX upgrade tokamak in Germany

 

Hold 9

Fabrication of MoTe2/MoS2heterostructures and measuring PL-signals

Alexander Skjøth(s230319), Rasmus Stegelman(s234452), Victor Behrndtz (s234464)

Vejleder: Xingyu Wang and Sanshui Xiao, DTU Electro

Resume:

Due to the expanding globalised society and increasing interest in artificial intelligence, there has been an increasing demand for more energy efficient telecommunications and computer components. For this reason the field of optoelectronics has gained a lot attention for its ability to increase the speed of interconnections by replacing electronic interconnections with optical interconnections, fo rexample fibre broadband. By replacing the electronic interconnections on a motherboard with optical interconnections, the communication between the CPU, RAM and other components will be faster, since the communication is done via photons, rather than electrons. The on-chip-interconnections won’t just be faster, but also be more energy efficient, due to the increase in speed. To achieve this we need use photonic emitters such as LEDs or lasers, which can work on a micro-scale. Since silicon isn’t suited for this, due to having an indirect band gap. MoTe2/MoS2 heterostructures with direct band gaps will be used instead, which excel in the transduction of electrical signals into photonic signals

 

Hold 10

Optical characterization of nanocavities

Jens Christian Skyum(s231551), Jeppe Happy Thrane Gøhler Hoffman(s234462)

Vejleder: Jesper Mørk,  and Valdemar Christian Bille-Lauridsen, DTU Electro

Resume:

Since the beginning of the Information Age, computers and digital technology have been a feature of the modern era, increasing the standard of living and the complexity of society. The use of complex electronic devices is an essential part of daily activities, increasing the consumption of energy. Resulting in an increasing demand for faster and more energy-efficient chips. A possible solution is replacing the traditional electrical circuits with optically integrated systems. These integrated systems have both commercial and environmental potential as they outperform electrical circuits in terms of speed and generate far less heat loss. The heat loss from electrical circuits comes primarily from the ohmic resistance between interconnected components. Further motivating photonic integrated circuits. This leads to the need for increasingly small lasers. Low-dimensional nanobeam laser structure fulfills this. With buried heterostructures as the gain medium, they have practical advantages such as their compact size and easy outcoupling into waveguides. Therefore the nanobeam structures are a promising candidate for future low-cost laser cavities

 

Hold 11

Simulation of electromagnetism for Single Photon Sources

Jesper Max Rohd(s234425), Laurits Danielsen(s234068)

Vejleder: josé Ferreira Neto, and Niels Gregersen, DTU Electro

Resume:

This projects aims to investigate nanophotonic geometries for single photon sources which are discrete sources used to generate Single photons that be used as optical qubits. The single photon sources are nanophotonic geometries that contain a single quantum dot that is the source of the single photon. The nanophotonic geometries will be simulated in a program so we don’t have to manufacture them to get data. Being able to generate optical qubits can be used for the Quantum internet that exploit quantum properties for enhanced security and Quantum computers that exploit quantum properties for parallelization. The simulation portion of the project will specifically look at distributed Bragg reflectors. The quantum dot is placed in the middle of a cylindrical structure, with a certain number of reflective layers on either side of the dot. The layers have varying reflective indices, and the purpose of the structure is using these layer to enhance the photon with constructive interference.

 

Hold 12

ummerisk simulering af udbredelse af bølger i plasma

Christian Cenni Pedersen (s220971), Magnus Valdemar Juul(s203890)

Vejleder: Stefan Kragh Nielsen, DTU Fysik

Resume:

Simulation and optimization of the microwave heating system In this project we aim to model the dispersive propagation of microwaves in a plasma with an inhomogeneous plasma density and magnetic field profile. In the transition towards a greener future humanity needs to alter its means of energy production. Still today, the holy grail of green power sources is nuclear fusion. In fusion reactors the objectiveis to achieve immense pressure and temperature for nuclear fusion to occur. A way in which this is being achieved is through heating free electrons with microwaves at specific regions in the fusion chamber where the microwaves couple to the oscillatory motion of the electrons. The aim is then to hit these electrons with microwaves that match the cyclotron frequency of these electrons and accelerate them hence heating the plasma further. Since the plasma is inhomogeneous it will disperse the microwaves such that their rays are not simply traveling in straight lines. Fortunately, this can be modeled with ray tracing, where the electromagnetic field is modeled as a collection of rays, each ray with a position dependent amplitude and phase. This problem is difficult to solve analytically due to the refractive index of plasma being highly dependent on electron density and the magnetic field applied, which fluctuate locally in the plasma. In this project we aim to develop a python script that can numerically simulate the propagation of microwaves through such a medium. This will be done solving progressively more complex models of the system, where the end goal is arriving at solving a 3-d model in the cold plasma theory adding customizability to shape and entrance angle of microwaves. Work goals for this fagprojekt 1. Plotting the refractive index as a function of the magnetic field and charge density. 2. Develop a script that can simulate the propagation of waves in the 1d case under the cold plasma model, solving the raytracer equations semi analytically. 3. simulate the propagation of waves in the 1d case using automatic differentiation instead of analytic expressions for the derivatives. 3. Solving the cold plasma model for the 3d case using automatic differentiation.3.5 Using the cold ray tracer to do a parameter scan to find, e.g. the optimal entrance angle or tosee the effect of varying the geometries of the density and magnetic field profiles.

 

Hold 13

Modelling of efficiency of electricity and hydrogen generation of a fusion power plant

Lea Elling Nielsen  (s234449), Nicklas Schiøtt Rueløkke(s234446)

Vejleder: Alexander Simon Thrysøe, Søren Bang Korsholm, DTU Fysik

Resume:

In the future cleaner energy is needed. One of the ways of doing this is fusion. The energy produced with fusion need to be economically sustainable as well as environmentally sustainable. Therefore, it makes sense to examine multiple ways of employing the energy. One way of using the energy is

producing electricity in a steam turbine, this can be described with the Rankine cycle. Another way of using fusion power is producing Hydrogen with the sulfur-iodine cycle. This cycle uses the thermal energy produced in a fusion reactor. Hydrogen can be used to power cars or create fertilizers.

 

Hold 14

Piezoelectric transducers for acoustofluidic applications

Agnete Cauchi(s234442), Messaoud Sofiane Benmessaoud(s232622)

Vejleder: Henrik Bruus, DTU Fysik

Resume:

Piezoelectric devices have many applications, including lab-on-a-chip technology, where they inso-called acoustofluidic devices can be used for microparticle handling in blood-bacteria separation, focusing of red blood cells and lipids, and more. In addition, piezoelectric transducers can be used to characterize properties of materials with ultrasound spectroscopy. When optimizing such applications, numerical simulations are often used to predict the performance of the devices, and it is therefore relevant to develop, implement and use such numerical models

 

Hold 15

Plasma modeling and experimental measurementson NORTH

Mert Emren(s234429), Mohammad Ali Maanaki(s234439)

Vejleder: Alexander Simon Thrysøe, Stefan Kragh Nielsen, DTU Fysik

Resume:

We are two engineering science students, who share similar views and ambitions towards the importance of sustainable energy in the near future. Although fusion is not yet practical for large-scale energy production, great progress has been made on this topic, such as with the NORTH tokamak at DTU. The reason for this is the extreme conditions required for fusion, such as the incredibly high temperatures and electron densities. These are precisely the parameters this project aims to measure through experiments. Following the experimental data collection, we will use a simulated model of NORTH to compare and analyze any disparities between the experimental data and the numerical simulation.

 

Hold 16

Optical Simulations Of Structured Materials

Leif Pedersen(s225221), Malte Sierslev(s234463)

Vejleder: Niels Gregersen, DTU Electro

Resume:

 

Hold 17

Exploring the spatial control of the conductivity betweenSrTiO3 and γ-Al2O3 using modern printing techniques

Albert Snoer Jensen (s234453), Emil Toftedal Hansen(s234435)

Vejleder: Felix Trier, Thor Hvid-Olsen, DTU Energy

Resume:

The electronic industry is the backbone of modern society, with an ever increasing demand of efficiency. It is, however, becoming increasingly more difficult to downscale these electronic devices. Therefore studies have begun looking into the material composition of oxides and the properties they possess. More specifically, the heterostructure between the oxides SrTiO3 andγ-Al2O3 have electrical properties, such as high carrier mobility and density, as well as extreme magneto resistance, which stems from the two-dimensional electron gas created between the layers. This study will focus on the interface between these two oxides, as well as designing different Hall bars to test how different length to width ratios affect the electrical conductivity. In order to optimise the Hall bars, it would be relevant to test how thin the conducting material can be, before the channel gets too narrow to carry any electrons, thereby preventing any conductivity. Optimising the amount of Hall bars per sample, would also entail testing how far apart we can space them, before they start affecting one another electronically.

 

Hold 18

Optical characterization and testing of nanolaser cavities

Gustav Frede Green Christoffersen (s234434), Emil Møller Knudsen (s234441)

Vejleder: Jesper Mørk , Matias Marchal, DTU Electro

Resume:

The development of nanolasers for computer chips has in recent years gained significant relevance, driven by the growing demand for faster and more energy efficient solutions. As traditional components approach their physical size limits, nanolasers offer an alternative, enabling optical communication on chips rather than relying on electronic signals. This change could improve both energy efficiency and communication speed. In developing these lasers, it is especially important to examine thermal effects, as they can have a major impact on the laser’s overall efficiency.

 

Hold 19

Plasma simulation for linear devices in COMSOL

Adrian Soares (s234433), Reknagel Nielsen(s234440)

Vejleder: Alexander Simon Thrysøe, DTU Fysik

Resume:

As of now, modern societies have been more and more dependent on dwindling resources of fossile fuel. That coupled with the increasing problems coming from CO2 emissions causing global warming, have made it clear, that we are in need of alternative sustainable energy solutions. One solution could be nuclear fusion, combining atomic nuclei together to produce energy. But although this method works on paper, the obstacle of producing a higher energy output is difficult and requires a lot of resources. For that purpose, research on nuclear fusion needs to be studied further by looking into the core concept, that is producing plasma. Matter that is turned into a plasma creates an environment, where nuclear fusion is easier to achieve, because of an abundance of charged particles in any combination of ions or electrons. But as plasma has unique and complex properties, such as a high temperature, the need for magnetic confinement, a high energy density, complex diagnostics and is electrically conductive, can make working with plasma a hassle and a hazard zone, when it is not created in a controlled environment. Therefore, a lot of experimental setups have been made to study and handle plasma to accomplish the goal of a higher energy output in nuclear fusion. One of these experimental setups used, are linear devices, that has advantages when it comes to studying plasma. With its linear configuration and easier to handle magnetic confinement, while also having accessibility to measurements and not to mention modular design, being easy to scale up or modify, making them adaptable for a lot of purposes. This project will therefore focus on simulating how plasma behaves in such linear devices, to help predict and improve experimental setups, which goal is to unravel the mysteries behind plasma to create an energy solution.   

 

Hold 20

Neutron and x-ray emission in the DTU Fusor

Jonathan Wennerberg(s234418), Philip Meyer(s234451)

Vejleder: Jesper Rasmussen, DTU Fysik

Resume:

The DTU-Fusor is an experimental device for creating plasmas and producing neutrons that can be used to research various aspects of fusion. The neutrons are created in fusion reactions, and X-rays are produced by bremsstrahlung emitted from the fusion plasma. One of the uncertainties with the Fusor is whether the X-ray- and neutron emission is isotropic or not, and what the energy distribution of the electrons that create the X-ray, looks like. These main uncertainties are what we wish to help clarify. It is therefore a good idea to create a model of the neutron distribution and transport in the Fusor, which we will accomplish through measuring the physical properties of the Fusor and inputting them into OpenMC, a Monte Carlo neutronics modeling package in Python, where we are able to simulate a realistic fusor and its transportation of neutrons through the wall of the Fusor chamber, that consists of different materials. The X-ray emission models are to be created from different X-ray relevant equations that we implement in Python to create spectra and graphs. Furthermore, if the analytical models aren’t accurate enough, we will apply more advanced numerical computational software.

The climax of the project is then to carry out measurements to check if these models accurately represent the processes in the Fusor. For the neutron distribution model, the neutron detector will be placed at various locations around the Fusor, to accurately compare with the simulation results.

For the X-ray emission models, the goal is to compare the measured spectra (intensities) at different voltages (the higher the voltage, the higher the acceleration of the electrons, leading to different X-ray spectra) and with different gasses, with the aforementioned models.

 

Hold 23

lineære magnetfelter, med og uden permanente magneter

Stig Kvistgaard Jensen (s234428), Emil Kenneth Elk (s234428)

Vejleder: Søren Bang Korsholm, DTU Fysik

Resume:

One of the most important tasks of modern-day science is the search for clean, renewable energy. Wind, solar and hydro energy have each been used, but have their respective limitations. Wind and solar are somewhat unreliable without incredible battery capacity, and hydro is stunted by the simple fact that there are only so many places on Earth where you can build a dam. Enter fusion energy. Fusion promises a clean, renewable energy source, provided we can make it work reliably. In a fusion reactor, energy is released from nuclear fusion reactions in super-heated plasma, held at millions of degrees Kelvin. A major challenge in the field of fusion energy is the creation of magnetic fields that keep the plasma in place. Our goal is to test a device that emulates the way a stellarator works, using permanent magnets. We will study and compare linear representations of 3 different ways of creating and/or simulating said fields: Coil-based (stellarator),magnet-based (the new device), and the ideal field, calculated numerically. We want to do this because getting accurate simulations for a linear field will eventually allow modelling and emulation of the corresponding toroidal field.

 

Hold 24

dTof measurements with pulsed laser andSPAD/MPPC for LiDAR technology

Asger Flindt Kirkebæ (234448), Eskild Præstholm (s234424)

Vejleder: Hao Hu, DTU Electro

Resume:

LiDAR imaging is used in numerous technologies and usage is continuously growing. One of the fundamental limiting factors of the technology is the detection of returning light, for which many technologies have been used such as Electron Multiplying Charge-Coupled Device (EM-CCD), Intensified Charge-Coupled Device (I-CCD), Avalanche Photodiode (APD), Single PhotonAvalanche Diode (SPAD) and Silicon Photomultiplier (SiPM). A promising technology in this field is the SPAD which utilizes the Avalanche effect in a reverse-bias configuration to measure instances of photon hits. The distance of objects can be measured with the time difference between the outgoing light and the returning light measured with the SPAD. The SPAD and the laser is crucial for increasing the range and quality of the distance measurement.

 

Hold 25

Performance characteristics of Graphene Field Effect Transistors with Ionic Gating

Lasse Søndergaard (s234458), Magnus Biehl Nielander (s234438)

Vejleder: Peter Bøggild, Bjarke Sørensen Jessen, Robert Steen Raunsgaar, DTU Fysik

Resume:

Graphene has the potential to revolutionize a wide range of industries. The aim of this project is to utilize graphene in a field effect transistor (GFET) with electrolytic gating to achieve carrier modulation substantially higher than that with electrostatic gating. This is realized through characterization of GFET’s from the Spanish graphene provider Graphenea, determining suitable electrolytes, and describing the doping and hysteresis effects nearly always seen in such devices. All of this work provides a useful platform for research and applications in biosensing and electrochemistry.

 

Hold 26

Design and Production of Special Alloys for Laser Powder Bed Fusion

Jacob Emil Andreasen (s223660), Albert Ljungberg Sørensen (s234460)

Vejleder: Niels Skat Tiedje, DTU Construct

Resume:

Metal additive manufacturing (AM) processes like LPBF involve rapid cooling and complex heat treatment cycles, resulting in microstructures and properties distinct from those seen in conventionally manufactured materials. This project focuses on atomizing and characterizing recycled tool steel to understand its suitability as a powder feedstock for AM, with the potential to develop tailored alloys for improved performance.