Hold 1
Characterization of plasma instabilities using high speed cameras
Marcus Atli Nadybal, Lærke Laura Bæk Nielsen, Alexander Johan Olsen
Vejleder: Stefan Kragh Nielsen, DTU Fysik
Resume:
Finding a stable, renewable, and clean source of energy is one of humanities most challenging and pressing issues, that simply needs a solution, if we want to continue society as it currently is. A promising source of this type of energy is fusion energy, utilizing the difference in energy levels before and after the fusion of nuclei. The fusion takes place within a reactor, that produces plasma. One of the most influential problems using plasma, is the instabilities that occur in the plasma, resulting in loss of energy output. The output/input ratio is defined as 𝑄; a measure of the reactor’s energy generating efficiency. The cause and occurrence of these instabilities will be the main focus of this project. One reason we know of is when charged particles are accelerated within the plasma. These particles will then oscillate, creating their own electromagnetic field, counteracting the applied magnetic field – which is there to ensure the containment of the plasma – causing instabilities in the plasma and thereby a diffusion and breakdown of the plasma, which results in a loss of energy output.
Hold 2
Characterization of a Nanoelectromechanical Spectrometer
Rasmus Kristiansen, Frederik Bylov Nielsen, William Marcus
Vejleder: Babak Vosoughi Lahijani, Søren Stobbe, DTU Electro
Resume:
Infrared spectroscopy is an important method of characterization in many industries, though most industrial scale spectrometers are highly precise they are also both bulky and expensive, which limits their wide-spread deployment in e.g. process monitoring and fieldwork. This has stimulated great interest in realising chipscale spectrometers based on scalable semiconductor production [1]. One such implementation is the Fouriertransform spectrometer (FTS) which utilises interferometry to generate an interferogram, and from this reconstruct the incoming spectrum. The particular chip-scale interferometer we will be working on has been developed and patented by our supervisors’ research group using novel bendable slot-waveguides to vary the index of refraction. The interference however is very difficult to model precisely so typically the reconstruction of spectra relies on empirical models. In this project we will extract the transfer-function and investigate the feasibility of a simple linear model for the reconstruction of a spectrum from a measured interferogram. The working mechanism will also be investigated with in-situ scanning electron microscopy (SEM). Linear models have already been applied to other FTSs with good results [2], and the goal of this project is to test whether this model is able to improve the performance of reconstruction for this design.
Hold 3
Produktion og brug af Zr-89
Rasmine Sofie Sund From, Amanda Liv Agerby
Vejleder: Andreas Tue Ingemann Jensen, Mikael Jensen, Kristina Søborg Pedersen, DTU Healthtech
Resume:
Positron Emission Tomography, also known as PET, is used to exoamine and diagnose tumors in cancer patients. PET uses the cancerseeking properties of radiolabeled monoclonal antibodies to create tomographical data. The data can then be used to examine the tumor, and thereby ensure the best treatment for the specific patient. The isotope 89Zr is one of the isotopes used in a PET scan. 89Zr is used for multiple reasons, some of them being: 1) Its decay properties, e.g., suitable half-life, 3.27 days. 2) The radionuclide itself is cheap to produce and therefore ideal for use in the hospital industry. 89Zr can be created by proton bombardment of a target in a cyclotron, after which 89Zr embedded in the target is separated. Therefore it is interesting to research whether it is possible to make a stable 89Zr target based of yttrium oxide and a thermal stabilizer. The reason yttrium oxide is attractive is that it contains less non-radioactive Zr than metallic yttrium.
Hold 4
Development of Pb-free Bi2Sr2Ca2Cu3O10 high temperature superconducting wires
Aleksander M. K. Christensen, Annika Dalsgaard Jensen, David Thomas Hart
Vejleder: Jean-Claude Grivel, DTU Energy
Resume:
The development of the high temperature superconductor Bi2Sr2Ca2Cu3O10 is usually made in a process where about 20% of the bismuth is replaced by lead. Despite the efficiency of this process the inclusion of lead goes against the push for more environmentally safe elements by the EU. Manufacturing of Bi2Sr2Ca2Cu3O10 superconductors without the inclusion of lead poses some difficulties. We will therefore manufacture a sample powder without the use of lead. Thereafter we will attempt multiple different doping processes to improve the reaction, in which a small amount of various other elements are included in the material (NaCl, KCl, B2O3, MgCl2typically around 0.5%), and to compare the conducting performance of wires from the different samples, including an undoped one.
Hold 5
Cu1 −xZnxFe2O4 Ferroelectric Film for Photocatalytic Water Splitting and Hydrogen Production
Hannah Leah Herlev Hvid, Nikoline Lykke Faurschou
Vejleder: Jean-Claude Grivel, DTU Energy
Resume:
Splitting H2O molecules into H2 and O2 molecules using sustainable energy sources is a promising process for
producing hydrogen, an interesting energy carrier for energy storage. The Cu1 −xZnxFe2O4 ferroelectric compound presents promising characteristics for this type of application, because its bandgap of 1.4-1.9 eV is in the suitable range for solar light driven water splitting. Furthermore, its pyroelectric properties may also contribute to hydrogen production upon temperature variations. The goal of this project is to develop a process to manufacture Cu1−xZnxFe2O4 films with a chemical solution deposition process and to test their water splitting ability.
Hold 6
Strong coupling between the light field and a mechanical oscillator
Thomas Borup Ravnborg, Christoffer Rykind Blarke
Vejleder: Alexander Huck, Daniel Allepuz Requena, DTU Fysik
Resume:
Our purpose with this project is to help in improving optical communication that is limited by the loss of photon’s quantum information. Finding a method to store the quantum information will help improving optical communication significantly and may also allow us to get better understanding of other fields such as quantum mechanics at a macro scale. This can be done by coupling a photon to a mechanical oscillator. This oscillator has to be build within a very small cavity and then the light has to be transmissioned into the cavity. Building this cavity and ensuring that the light gets into the cavity and stays there is what our project is about.
Hold 7
Impact of plasma current on plasma transport
Lucas Christopher Dybendal Maack, Thor Tane Schou Nielsen Deibert
Vejleder: Stefan Kragh Nielsen, DTU Fysik
Resume:
With a growing global population and higher standards of living, problems such as an increasing demand for energy and a lack of alternative energy sources are growing more relevant. Combined with global warming the need for green energy sources is becoming more prevalent. A potential solution for this problem is fusion energy, but due to a lack of research, the technology within this field is not yet ready for commercial use. One of the greater challenges with fusion power is plasma turbulence which decreases stability and efficiency. To further understand this problem we aim to calibrate an instrument called a ’Rogowski coil’ and further test it on DTU’s tokamak fusion reactor NORTH. We will calibrate the Rogowski coil with the use of a known current in an isolated system to measure the change in voltage. By extrapolating data and integrating over the output, compared to the input it is possible to correlate the magnetic flux and then determine the number of windings of the Rogowski coil. When the Rogowski coil has been calibrated we can use it to read the amount of current in the plasma and by using other diagnostics compare the amount of current to the plasma turbulence and see if running a current through the plasma minimizes loss of plasma particles.
Hold 8
OPTIMIZATION OF MAGNESIUM DIBORIDE SUPERCONDUCTORS
Christopher W. Toft, Malthe B. Petersen
Vejleder: Jean-Claude Grivel, DTU Energy
Resume:
With the increasing need for superconductors, the need for optimizing said conductors rises. The conventional method for producing magnesium diboride (MgB2) superconductors focuses on speed and cost-effectiveness, resulting in lesser quality. With an alternative heat treating process, we wish to achieve a superconductor with less porosity and better superconductive proberties. By testing and comparing different heat treatments, we can determine the best heat treatment process.
Hold 9
2nd harmonic heating in magnetically confined plasma
Johan Holmgaard Nielsen, Linnea Jensen de Leon, Maximus Marsella Rosenstrøm
Vejleder: Stefan Kragh Nielsen, Riccardo Ragona, DTU Fysik
Resume:
Fusionenergy is a worthy research subject since it helps produce cleaner renewable energy with no radioactive waste. Fusion energy can be produced in a so called tokamak, this process happens in ionized gas, or so called plasma, that is magneticlly confined and reaches up to a million degrees celsius in a tokamak. The gas is heated with harmonic microwave frequencies. In our project, we want to research if the introduction of second harmonic frequencies creates turbulence within the waves of plasma and if the usage of second harmonic frequencies instead of first hammonic frequencies, improves the energy efficiency of the tokamak. At DTU we have a reduced scale tokamak that we will use for our experiments in this project.
Hold 10
Mass Transport in Nanochannels
Samson Alfred Adsersen, Niels-Gabriel Gaillard
Vejleder: Kristian Speranza Mølhave, Emil Christian Stillhoff Jensen, Mads Søndergaard Larsen DTU Nanolab
Resume:
In recent years, the field of Liquid Phase Transmission Electron Microscopy - a technique used to view the behavior of nanoparticles and chemical reactions in liquid – has been on the rise, using nanofluidic chips as a window into this new world of microscopy. The electrons will interact with everything in their path, which makes it necessary to reduce the amount of surrounding bulk material i.e. working on very small scales – pictures are not great in cases of channels bigger than 200 nm. However, this means that the boundary conditions (surface potentials) have a much bigger relative influence on the observed sample. In this fagprojekt were working with a startup company (InsightChips) that produces these types of chips. Our goal is to characterize the effect of surface potentials on the movement of such samples, in the nanochannnels of their chips, using basic principles of hydrodynamics and electrokinetics; specifically electroosmosis and electrophoresis. Experimental results will be evaluated through image processing in Python, but also validated from finite element method simulations with COMSOL.
Hold 11
Time-resolved X-ray Solution Scattering on Aqueous Systems
Niels Pelle, Kian Latifi
Vejleder: Martin Meedom Nielsen, Verena Isabell Markmann, Morten Lunn Haubro, DTU Fysik
Resume:
In liquid phase chemistry and biology many interesting reactions and processes takes place in aqueous solutions, which includes the transportation of compounds in blood and diffusion of ions across cell membranes. In many of these processes, water either stabilizes the process or acts as an outright reaction partner. Therefore understanding these processes, requires an intimate understanding of interactions between solute and solvent. This project will focus on investigating water as a solvent and reaction partner by analyzing time-resolved X-ray solution scattering (TR-XSS) data, which provides structural information on molecular length-scales and on the time-scales of chemical reactions. We will model the direct excitation of water molecules as a function of excitation power from a laser pump pulse. Finally, we will discuss whether the model offers a full description of the excitation of water.
Hold 12
Stainless steel
Alba B. Larsen, Johannes Varnes, Marika B. Norby
Vejleder: Thomas Lundin Christiansen, Marcel Adrianus Johannes Somers, DTU Mechanics
Resume:
Stainless Steel is used in many different industries which require many different properties, such as low nickel concentration for implants. Therefore, many different steel alloys are created to serve various purposes and different methods are developed to improve performance. HTSN (High temperature solution nitriding) is one method used to implement nitrogen in high-alloy steels, where the nitrogen is dissolved in the steel at high temperature to get higher corrosion and deformation resistance and to minimize dichromium nitride precipitation.
Hold 13
Analysis of crystalline properties of III-V materials epitaxially grown on silicon
Lucas Borg Clausen, Elias Kjelstrup Bakhauge, Jakob Andreas Finne
Vejleder: Elizaveta Semenova, DTU Electro
Resume:
III/V materials are necessary for active photonic and high speed electronic applications, due to their direct bandgap structures as opposed to Si which has a indirect bandgap this means that III/V semiconductor components can absorb and emit photons with much higher efficiency than Si it would therefor be very attractive to implement III/V components into exciting Si semiconductor electronics because of Si electronics very mature fabrication process and high robustness. We therefore want to understand what kind of defects occur in these III/V materials as the amount of defects or the severity of these could be lowered or corrected for. This would help industries such as the telecom and computer industries.
Hold 14
Iron-based superconductors for ultrahigh field applications
Albert Ibsen Andersen, Julie Wolf
Vejleder: Jean-Claude Grivel, DTU Energy
Resume:
The expulsion of a magnetic field from a superconductor during its transition to the superconducting state, when it is cooled below the critical temperature is called the Meissner effect. This effect was discovered by the German physicists Walther Meissner and Robert Ochsenfeld in 1933. Since then a lot of the research into superconductors has been done to find more readily available materials and materials with a higher critical temperatures. In 2008 a family of iron based superconductor was discovered. These are the ones we will be studying. A superconductor don’t have any electrical resistance. This can be used to make a really strong electromagnet called a superconducting magnet. These magnets have been utilised in various ways including: MRI and NMR machines, mass spectrometers, and beam steering particle accelerators and some tokamaks. They have also been used in turbines to overcome restrictions imposed by high electrical current [1].
Hold 15
Exploring the physics of electromagnetic harvesters
Ditte Stuhr Petersen, Jeppe Elias Ekberg Jensen, Jonathan Bechsofft Mikkelsen
Vejleder: Rasmus Bjørk, DTU Energy
Resume:
An electromagnetic harvester is a small and relatively simple physical device that can harvest energy from vibrations by moving a permanent magnet relative to one or more electromagnetic coils, thereby inducing a current that can be harvested. In this project we will consider a 1D harvester, where a permanent magnet is contained within a tube, floating between to other permanent magnets that are fixed at the ends of the tube. Such vibrations harvesters are a possible way to produce energy for remote devices, that have a low power requirement and no attached power source, like many sensors connected over the internet. Compared to a battery, they could potentially be cheaper, as they don’t need to be replaced unless they break. These harvester devices are interesting to study, as the magnetic force in such a device is highly nonlinear, and exhibit hysteresis, as is the force resulting from the interaction between the magnet and the coil, so the dynamics of the device are not trivial.
Hold 17
Sound coming out of the ear - an epiphenomenon of auditory function
Philip Jensen.
Vejleder: Bastian Epp, DTU Healthtech
Resume:
Otoacoustic emissions is a phenomenon that is a relatively new discovery. It has been shown that otoacoustic emissions disappear after damage to the inner ear. Uses such as hearing test on infants
have already been implemented and is widely used to do early diagnostics of hearing impairment. It has been hypothesized that the Van der Pol oscillator can model these otoacoustic emissions and
research on this could lead to new discoveries regarding hearing impairment and/or new applications for the van der pol oscillator
Hold 18
Optical loss mechanism analysis of silicon carbide waveguides
Vilma Klemp, Malene Hamburger
Vejleder: Haiyan Ou, DTU Electro
Resume:
Leveraging the mature material growth and fabrication technology, silicon carbide (SiC) is emerging as a potential material platform for integrated nonlinear and quantum photonics because it has outstanding optical properties such as high second order and third order nonlinearity, high refractive index, and broad transmission window. Additionally, many point defects in this material are optically addressable, enabling it good candidate for single photon sources. But before all these potential applications are turned into reality, demonstration of low-loss SiC waveguides is a fundamental requirement. The loss in SiC waveguide consists of two parts. One part is from material, and the other part is from fabrication. Material loss includes absorption and scattering. Fabrication loss mainly includes scattering from surface roughness.
Hold 19
Broadband optomechanical non-linearities
Sander Jæger Linde, Magnus Vejby Nielsen
Vejleder: Søren Stobbe, Guillermo Arregui Bravo, DTU Electro
Resume:
The idea of an all-optical computer has been an unreachable dream for years, as electricity hasfundamental issues which light avoids. To reconquer the above-mentioned dream, an optical switchis needed. In order to create an optical switch it has been proposed to use optical gradient forcesto move mechanical objects. These gradient forces are best observed in waveguides. Earlier studieshave shown that the optomechanical forces act upon slot waveguides. Usually slot waveguides arefixed at the ends but by decoupling these the optical forces could allow for these to function as anoptomechanical switch. It is therefore interesting to investigate how a waveguide can be suspendedin order to take advantage of the optomechanical forces acting upon it
Hold 20
Removal of residue from PVA transfer of CVD grown graphene
Mikkel Ravn-Feld, Mikkel Christian Larsen
Vejleder: Abhay Shivayogimath, DTU Fysik
Resume:
The past decade has seen a rise the the applications of graphene. Today, large sheets of graphene can be synthesised using the chemical vapor deposit method (CVD), in which a single layer of graphene is deposited onto a piece of copper foil. Conventional methods of graphene transfer are costly. PVAtransfer is an alternative approach. The graphene is first transferred to a water soluble piece of PVA using a laminator to supply heat and pressure. Then, the PVA is transferred to substrate after which the substrate is covered with water, which will dissolve the PVA. However a small amount of residue is left after this process, which strongly affects the properties of the graphene. In this project we will subject the transfered graphene to a variety of treatments which can remove the leftover residue. We will use Atomic Force Microscopy (AFM), Optical Microscopy (OM) and water contact angle meassurements to determine the contamination level of the graphene before and after treatmeant. The structural quality of the graphene must also be intact, so using Raman Spectropy before and after treatment we are able to determine if our treatment may cause damage to the sheet.
Hold 21
Capping Silver
Bjarke Linnetved, Troels M. Asmussen, Omar Jennane
Vejleder: Radu Malureanu, DTU Electro
Resume:
Silver is, in theory, one of the better materials to use when it comes to optics, in particular for plasmonic applications, but it lacks chemical stability thus oxidizing very fast. We will investigate the possibility of using an aluminium oxide layer to cap and protect the silver. It should limit the oxidization of the silver layer and allow it to be used in plasmonics. The main objective is to analyze mixed silver and aluminium thin film deposition (co-sputtering), investigate if (and how quickly) the aluminium in the mixture migrates to the surface, and if the aluminium oxidizes during deposition, or after migrating to the surface. We will be testing the elemental composition of the material, its behavior and properties but will not use it in plasmonic structures.
Hold 22
Fabrication and charactization of silicon bottom cell devices for integration in tandem solar cells
Malli Segoli, Rasmus Torp
Vejleder: Rasmus Nielsen, Peter Vesborg, DTU Fysik
Resume:
There is a desire to become less reliant on fossil fuels due to factors such as climate change and our current energy crisis. Solar cells offer an alternative source of electrical energy; their efficiency and in turn cost are therefore paramount. Single junction solar cells are however limited to an efficiency of about 33% while two junction tandem solar cells has a peak efficiency of 45%, as two junctions with different bandgaps can utilize a wider part of the Sun’s spectral range. Silicon cells have an almost optimal bandgap for use as a bottom cell. However the p-n junction is a very sensitive part of the solar cell and the doping density of boron affects the carrier lifetime. It is therefore relevant, to investigate the effects of change in the boron doping density.
Hold 23
Nano-optoelectronic devices: Integration of electronic and Photonics
Sarah Vestergaard, Clara Wimmelmann
Vejleder: Ayman Nassar Kamel, Kresten Yvind, DTU Electro
Resume:
The exponential growth in information traffic today calls for less energy needed per bit to be sustainable, and while transistor size and logic energies keep up with Moore’s law, energy dissipation due to electrical on- and off-chip interconnects cannot. A significant amount of this energy dissipation is caused by wire charging and discharging and electronic circuits to maintain electrical signal such as amplifiers and timing recovery. In contrast, optics in waveguides does not have wire capacitance, and thus optoelectrical interconnections is a promising technology to decrease the energy needed per bit. To integrate optics into the electrical circuits on chip, a light emitter as well as detector is needed. Decreasing the size of these components entails less energy consumption, however smaller detectors are usually not efficient enough. It is therefore interesting to design energy efficient detectors using extreme dielectric confinement (EDC) in a wellknown and commercially attractive material as Silicium.