For the academic year 2026/2027, the Institute of Electrical Engineering of the Slovak Academy of Sciences (IEE SAS), v.v.i. is announcing the following PhD thesis topics for the study programs:
- Physical Engineering (FEI STU)
- Electronics and Photonics (FEI STU)
- Physics of Condensed Matter and Acoustics (FMFI UK)
Physical Engineering
Topic: Preparation and characterization of Ga2O3-diamond heterostructure UV photodetectors
Supervisor: Ing. Marián Varga, PhD. (Department of microelectronics and sensors)
Co-advisor: Ing. Filip Gucmann, PhD.
Description: One of the most significant challenges of the recent years, related to the development of new electronic devices and having potential for major improvement of the current status in a vast variety of human activities can be found in the field of solar-blind (SB) ultraviolet (UV) photodetectors (PDs). Novel UV PDs, especially for deep-UV (DUV) optoelectronics (wavelengths shorter than 280 nm) are needed. These cannot typically be manufactured from conventional materials. This resulted in the development of ultrawide bandgap (UWBG) semiconductors (such as AlxGa1−xN, hBN, Ga2O3, and diamond) and their utilisation for SB UV PDs. Gallium oxide (Ga2O3), a naturally n-type semiconductor, represents a suitable UWBG material, showing a very good potential and capability to significantly improve the current state-of-the-art electronic devices. Furthermore, synthetic diamond has gained a strong reputation to be an exceptionally versatile material due to its attractive physical and chemical properties and availability of facile preparation of films with p-type conduction. On the other hand, it is very difficult to prepare p-type Ga2O3 and n-type diamond.
In this work, we will target the development and detailed characterisation of new high-performance DUV SB PDs with p-n or p-i-n device structure, comprising n– and i-type Ga2O3 and p-type diamond. Such heterostructure devices represent a favorable solution combining the best of the two UWBG worlds. The Ga2O3 layers will be grown by liquid-injection metal-organic chemical vapour deposition (LI-MOCVD), a growth technique developed at IEE SAS. Polycrystalline diamond films will be prepared by MW plasma-enhanced CVD method in close cooperation with the Institute of Physics of the Czech Academy of Sciences in Prague. UV PDs and other electronic devices will be fabricated using modern techniques and tools available at the IEE SAS, i.e. optical or electron-beam lithography, reactive ion etching, and thin films deposition. The designed periodic structures, electric contacts, interdigitated arrays, and van der Pauw test structures will be prepared using a metallic mask prepared by the vacuum sputtering or evaporation through lithographically-prepared masks and patterned by a lift-off process.
The main goal of this PhD thesis is the fabrication, characterisation, and deep understanding of the effects at the Ga2O3-diamond heterostructure interface, and to assess their influence on the properties of such a heterojunction. In addition, focus will be also on testing of the properties of prepared UV photodetectors and their radiation hardness when exposed to the ionising radiation.
Topic: Analysis of the Influence of Doping on the Properties of Ultrathin Layers of Transition Metal Dichalcogenides
Supervisor: Mgr. Michaela Sojková, PhD. (Department of microelectronics and sensors)
Description: The discovery of graphene has sparked extensive research into other 2D materials. Transition metal dichalcogenides (TMDs), with the general formula MX2, where M represents a transition metal (e.g., Mo, W) and X is a chalcogen (S, Se, Te), have gained particular attention. These materials have a layered structure and, depending on their crystalline structure, can exhibit diverse electrical properties (semiconducting, metallic, superconducting, etc.). According to theoretical calculations, TMD materials offer unique characteristics such as high flexibility, enhanced charge carrier mobility, and electronic or optical properties dependent on the number of layers, making them suitable for a wide range of applications. However, many predicted properties of these materials, especially charge carrier mobility, have not yet been experimentally achieved. One approach to improving the electrical properties of 2D-TMDC materials is doping, similar to the doping of semiconductors with desired impurity elements.
This research will focus on the preparation of doped ultrathin TMD layers. A two-step method will be employed, where thin layers of metals or their oxides are first deposited using magnetron sputtering or evaporation. In the second step, these layers will be annealed in the presence of sulfur or selenium vapors (known as sulfurization/selenization) along with the dopant sulfide. The influence of the dopant on the structural, optical, and electrical properties of 2D material layers will be investigated. Various types of TMDs (e.g., MoS2, PtSe2, NbSe2) will be prepared, and multiple metals and their combinations (Ni, Cu) will be used for doping. The prepared layers will be analyzed using X-ray diffraction analysis, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, optical measurements, electrical property measurements, and other characterization techniques.
The work will be carried out at the Institute of Electrical Engineering of the Slovak Academy of Sciences (IEE SAS), which is equipped with the necessary technological and characterization facilities. The PhD student will gain versatile skills with numerous experimental methods and will actively participate in collaborations within several projects.
Topic: Influence of different substrates, buffer layers and modulated concentration profiles on the microstructure and electric properties of epitaxial layers of Ga2O3 and related compounds deposited via metalorganic chemical vapour deposition (MOCVD)
Supervisor: : Ing. A. Rosova, CSc. (Department of III-V Semiconductors)
Co-advisors: Ing. Zdenko Zápražný, PhD.
Description: The ultra-wide-bandgap semiconductor Ga₂O₃ has attracted significant attention in materials research in recent years as a promising material for high-power and high-voltage switching and rectifying electronic devices, as well as for optoelectronic structures for the solarblind detection of ultraviolet radiation in the UV-C spectral range. While homoepitaxial layers currently set the benchmark in terms of crystalline quality and electrical properties, the growth of high-quality epitaxial layers on technologically relevant substrates (e.g., Al₂O₃, SiC, Si) remains a major research challenge due to the high density of defects, in particular domain boundaries between crystallographic domains of different orientations.
This work will focus on the investigation of the microstructure of Ga₂O₃ epitaxial layers and related alloys prepared by metal–organic chemical vapor deposition (MOCVD) at the Institute of Electrical Engineering of the Slovak Academy of Sciences. Modifications of the microstructure, and consequently of the layer properties, will be achieved by varying the foreign substrate, usage of buffer layers (e.g., (AlₓGa₁₋ₓ)₂O₃), and/or by fabricating heterostructures with modulated composition. Particular emphasis will be on evaluation of mechanical strain induced by the substrate–layer interface during epitaxial growth.
The primary techniques for microstructural characterization will include transmission electron microscopy (TEM), X-ray diffraction (XRD), scanning electron microscopy (SEM), and elemental analysis by energy-dispersive and wavelength-dispersive spectroscopy (EDS and WDS). The influence of selected growth parameters on the electrical properties of the prepared Ga₂O₃ layers (e.g. carrier concentration and mobility), will also be investigated. The work will be carried out within the framework of a joint project with the Taiwanese partner ITRI (Industrial Technology Research Institute).
Topic: Growth and properties of III-N quantum structures for fast electronic
Supervisor: : Ing. R. Stoklas, PhD. (Department of III-V Semiconductors)
Co-advisors: Ing. Michal Blaho, PhD, Ing. J. Kuzmík, DrSc.
Description: Topic of the work deals with the growth and investigation of epitaxial III-N quantum structures prepared by metal-organic chemical-vapor deposition (MOCVD). GaN, as a constituting member of III-N family, is a most dynamically developed material in semiconductor industry marked by a Nobel Prize for invention of blue/white LEDs. III-N materials are currently attracting a lot of interest also for applications in power, high frequency, and automotive electronics.
Compound semiconductors based on III-N materials (GaN, AlN, InN) and its combinations facilitate preparation of countless heterostructures showing quantum effects. In particular, 2-dimensional charge carrier gas with high density and mobility can be created; both these properties represent crucial aspects for future electronic devices. Similarly, InN represents the material with the highest electron drift velocity among all common semiconductors. Work will be focused on mastering the growth at the state-of-the-art AIXTRON MOCVD system. Main emphasize will be given to heterostructure quantum wells containing In(Al)N for future ultra-fast transistors, as well as preparation of the channel layer based on InN. Material study will include several techniques for structural, electrical and optical investigation. PhD study will be accomplished by processing and demonstration of test structures and innovative electronic devices.
Topic: Electrical transport in thin layers of some TMDC materials
Supervisor: RNDr. Martin Hulman, PhD. (Department of Physics and Technol. at Nanoscale)
Description: In the past two decades, materials characterized by significant dimensional anisotropy have become one of the most extensively studied subjects in solid-state physics and materials research. This category encompasses transition metal dichalcogenides (TMDCs), compounds composed of elements such as S, Se, and Te, in conjunction with metals like Mo, W, and Pt. Substances with the chemical formula MX2 can be synthesized in extremely thin layers.
At the Institute of Electrical Engineering, a team is dedicated to preparing thin layers of TMDC materials and conducting their characterization. The proposed dissertation would complement the endeavors of this group. The focus of the dissertation lies in examining the electrical transport properties of (ultra)thin layers of TMDC materials, particularly those within the subgroup exhibiting semi-metallic and metallic characteristics. The work predominantly entails experimental research. While it entails some involvement in the growth of thin layers, the primary emphasis is on measuring transport characteristics. In addition to transport characterization, the dissertation will explore the impact of temperature, doping, and structure on the conductivity of 2D materials.
Throughout the dissertation, the student will engage with vacuum and low-temperature facilities. The experimental findings will be analyzed in accordance with various models of solid-state physics. Furthermore, the student is expected to present their results at both domestic and international conferences, necessitating proficient spoken and written English skills.
Topic: Functionalizing powders for novel nanocomposites using atomic layer deposition
Supervisor: Ing. Boris Hudec, PhD. (Department of Physics and Technol. at Nanoscale)
Co-advisor: MSc. Helle-Mai Piirsoo, PhD.
Description: Nanostructured composites have a lot of potential as nanoscale effects can modify materials’ mechanical, optical, magnetic, or electrical properties compared to bulk. Coating powders or nanoparticles with a conformal, nm-thick films dramatically improves their mechanical properties and chemical stability through grain boundary engineering. However, coating micron sized powders, not to mention nanoparticles, in a controllable conformal manner remains a challenge. When designing these nanocomposites, the industrial scalability as well as the environmental impact must be considered.
The aim of this PhD thesis is to systematically investigate two complementary chemical deposition methods on various metal and ceramic powders for application in new battery electrode chemistries. Atomic layer deposition (ALD) with fluidized bed reactor (FBR) and an in-situ mass-spectrometer will be used for deposition and in-situ process analysis of different metal oxides (Al2O3, TiO2, ZnO, ZrO2…). New complementary solution-based deposition method will be used to coat nanoparticles in an inert environment in a glovebox. Materials made using both approaches will be characterized by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and X-ray diffraction (XRD).
The student will be a part of a research team working on the topic in frame of ongoing research projects. We are looking for creative and dedicated team players, prior experience in related areas is a plus.
Topic: Novel multi-physics modelling methods of superconducting high-field magnets and power applications
Supervisor: Mgr. Enric Pardo, PhD. (Department of Superductors)
Co-advisor: MSc. Anang Dadich, PhD.
Description: High-temperature superconducting electromagnets can generate extremely high magnetic fields beyond 40 T. These magnets enable cutting-edge fundamental research on materials and particle physics experiments, especially when using superconducting accelerator magnets like those in CERN. Superconducting magnets are also very promising for compact fusion reactors for emission-less clean energy and ion propulsion for spacecrafts. Other superconducting power applications can also reduce emissions, such as electric propulsion motors for hydrogen-electric aircraft and high-power wind generators. Designing all these applications require multi-physics computer modelling of their electromagnetic, thermal and mechanical properties. This PhD intends to develop novel multi-physics numerical modelling methods that go beyond finite-element methods in order to speed-up computations, which allows to model more complex devices and obtain novel insights. The newly developed models, which the student will program in C++, will be able to run in supercomputers like Devana in the Slovak Academy of Sciences. The new models will grow from our own software, following our guidance and experience. The student will be able to attend to international conferences in Europe and beyond once a year. This work will be part of our national projects and international collaborations that we gained from European Horizon 2020 projects, such as CNRS (Grenoble, France), CEA (Saclay, France), and HZDR (Dresden, Germany). This PhD joins knowledge from Physics, Engineering, Mathematics and Computational Sciences.
Topic: Study of current distribution and AC losses in superconducting windings made of filametized tapes
Supervisor: Mgr. Mykola Soloviov, PhD. (Department of Superductors)
Description: High-temperature superconductors represent advanced materials for the fabrication of coils, cables, and other components of high-performance electrical devices. The safe and stable operation of such devices requires cooling to the operating temperature and maintaining the superconducting conductor at this temperature. From an application perspective, it is essential to accurately estimate the heat generated by AC losses in superconducting materials operating in an alternating magnetic field.
A well-known way to reduce AC hysteresis losses is to divide the superconducting layer into narrow sections, a process known as filamentization. The AC loss reduction in filamentized tapes was confirmed in transposed superconducting cables, but the applicability of such a technology in small coils remains unknown. Additionally, the current redistribution between filaments plays a key role in the safe and stable operation. Point defects in filamentized tapes may cause current redistribution through the metallic stabilizing layers, which must be considered. The flow of current through the metallic stabilizing layers also contributes to heat generation in the superconducting coil.
Within this PhD project, a series of experiments on various superconducting windings will be carried out, complemented by numerical finite-element modelling to better clarify and understand the underlying physical processes. This is important for the practical application of the new generation of low-loss superconducting tapes.
Electronics and Photonics
Topic: Vertical GaN MOS structures with semi-insulating channel for high-power switches
Supervisor: : Ing. R. Stoklas, PhD. (Department of III-V Semiconductors)
Co-advisor: Ing. J. Kuzmík, DrSc.
Description: Semi-insulating vertical GaN devices are a class of power semiconductor devices that utilize Gallium Nitride (GaN) material in a vertical configuration, offering significant advantages for high-voltage, high-current, and high-frequency applications. The semi-insulating GaN layer helps to reduce parasitic capacitance, mitigate leakage currents, and improve breakdown voltage, making these devices highly suitable for power electronics, RF amplifiers, and motor drives. By incorporating vertical structures, these devices achieve high current handling capabilities while maintaining efficient thermal management. The combination of GaN’s wide bandgap, high electron mobility, and semi-insulating properties results in improved performance, making vertical GaN devices an ideal choice for next-generation power systems. In vertical devices, it’s crucial to ensure uniform current flow across the entire device area. Structural modifications like current spreaders, channel over-growth or optimized electrode designs help mitigate current crowding effects, improving the channel’s performance. In addition, the channel over-growth process also enhances the interface quality between the gate and the GaN material, which is critical for device reliability and performance. A vertical MOS structure on GaN through channel over-growth is an advanced approach to fabricating high-performance electronic devices. This method involves over-growing a semiconductor layer to form a high-quality gate channel, typically using selective epitaxial growth. The configuration of the semi-insulating vertical GaN transistor designed by us is patented in Slovak Republic; A patent application has also been filed within the EU.
The main aims of the PhD thesis will be an understanding of the basic principles of the GaN vertical structures. Electrical characterization of vertical GaN devices involves assessing key parameters such as breakdown voltage, current-voltage characteristics, capacitance, and on-resistance. These metrics provide insights into the device performance under different operational conditions. High breakdown voltages and low on-resistances are particularly critical for optimizing device efficiency and minimizing energy losses. Mechanisms of failure, including thermal stress, gate oxide breakdown, and defect-related degradation will be also analysed.
Topic: Preparation of p- and n-type transition metal dichalcogenide layers for CMOS-compatible electronics
Supervisor: Mgr. Michaela Sojková, PhD. (Department of microelectronics and sensors)
Description: The thesis will focus on the development of scalable and CMOS-compatible technologies for the fabrication of field-effect transistors (FETs) based on transition metal dichalcogenides (TMDs). TMDs are layered materials with the general formula MX₂, where M denotes a transition metal (e.g., Mo, W) and X is a chalcogen (S, Se, Te). Owing to their atomically thin nature and tunable electronic properties, TMDs represent promising channel materials for next-generation FET devices that can surpass the limitations of conventional silicon technology. However, their practical implementation is still hindered by challenges related to large-area synthesis, contact engineering, and compatibility with standard CMOS processes.
The main objective of the thesis will be the realization of both p-type and n-type TMD-based FET devices integrated on a single technological platform, enabling complementary transistor operation analogous to CMOS logic. The work will focus on the controlled synthesis of high-quality TMD thin films using CMOS-compatible deposition and chalcogenization techniques, as well as on their direct integration into FET architectures with both bottom-gate and top-gate configurations. A two-step method will be employed for TMD preparation, in which thin metal or metal oxide layers are first deposited by magnetron sputtering or thermal/e-beam evaporation, followed by annealing in the presence of sulfur or selenium vapors (sulfurization/selenization).
The fabricated layers and device structures will be characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, optical measurements, electrical transport measurements, and additional analytical techniques. The work will be carried out at the Institute of Electrical Engineering of the Slovak Academy of Sciences (IEE SAS), which is equipped with the necessary technological and characterization facilities. The PhD student will gain versatile skills with numerous experimental methods and will actively participate in collaborations within several projects.
Topic: Neuromorphic systems adopting nanoelectronic memristors
Supervisor: Ing. Boris Hudec, PhD. (Department of Physics and Technol. at Nanoscale)
Co-advisor: prof. Ivan Sekaj, PhD., Inst. Robotics and Cybernetics FEI STU
Description: This PhD thesis aims to investigate memristive devices as a key component of neuromorphic hardware systems. The research will focus on the design, fabrication, and characterization of thin-film memristive structures and their integration into hardware neuromorphic systems, with potential applications in smart in-/near-sensor computing and robotics. The goal is to contribute to the development of scalable, energy-efficient computing architectures inspired by biological neural systems.
The expertise acquired by the student in the scope of this theses will cover thin film deposition and cleanroom nano-fabrication techniques with a focus on atomic layer deposition (ALD), material analyses and electrical characterization techniques, and understanding of the hardware neural networks based on emerging devices.
The thesis will be a part of a wider project and the student will become a part of our research team. We are looking for creative and dedicated team players, prior experience in related areas is a plus.
Topic: Study of transport properties of Ga2O3 transistors for applications in kV range
Supervisor: : Ing. M. Ťapajna, PhD. (Department of III-V Semiconductors)
Co-advisor: Ing. Ondrej Pohorelec, PhD.
Description: Gallium oxide (Ga2O3) is an emerging ultrawide bandgap (UWBG, Eg=4.8–5.3 eV) semiconductor material, recently recognized as a highly promising for high-voltage (HV) and high-power applications. This material can enable solid-state diodes and transistors with unprecedented blocking voltages, far exceeding the capabilities of mature technologies based on main competing compound semiconductors, i.e. GaN and SiC. Ga2O3 devices can thus enable development of systems for transportation utilising electric drive (cars, trains, ships, aircrafts) or transformation for high-voltage DC power distribution networks. Currently, great research effort is focused on growth of Ga2O3 and development of related electronic devices for power applications.
The aim of the work will be the study and detailed characterization of the electrical breakdown of transistors and diodes based on heteroepitaxial Ga2O3 layers prepared at the Institute of Electrical Engineering SAS using chemical vapor deposition methods. The work will be focused on identification of the electrical breakdown modes and description of the breakdown mechanisms in order to propose an optimal design for increasing the blocking voltage of the studied devices. In addition, standard reliability tests (HTRB, HTGB) of the prepared devices will be carried out in order to identify the parasitic instabilities of the electrical device parameters. These results will contribute to the understanding of the specific degradation modes in Ga2O3 power devices and their mitigation.
Topic: Suppression of rotational domain formation during heteroepitaxial growth of Ga₂O₃ by the metalorganic chemical vapour deposition (MOCVD)
Supervisor: : Ing. Filip Gucmann, PhD. (Department of III-V Semiconductors)
Co-advisor: Ing. Michal Blaho, PhD.
Description: Almost one third of all produced electricity passes through power electronic devices at some stage before consumption with the predicted increase up to 80 % for the next decade. Therefore, even small efficiency improvement of power electronics represents significant energy savings and reduction of carbon emissions. One of the ways to achieve higher efficiency of power electronic devices is the use of new (ultra) wide bandgap (Eg) semiconductor materials. Gallium oxide (Ga2O3) is a good example of such material – with Eg ~4.9 eV and high critical field which surpasses those of the mainstream semiconductors for power switching in the range up to several kVs (Si, SiC, GaN). Ga2O3-based devices can be also invaluable for faster deployment of electric means of transport thanks to development of faster charging systems and more efficient energy transfer between batteries and electric drivetrain. It can also significantly contribute to improve efficiency of power conversion generated by renewable sources (solar, wind).
The main objective of this thesis will be the investigation and optimisation of epitaxial growth of thin Ga₂O₃ layers, and related materials such as (AlₓGa₁₋ₓ)₂O₃, on foreign substrates (Al₂O₃, SiC, Si) using metal–organic chemical vapor deposition (MOCVD). A particular emphasis will be on suppressing the formation of rotational domains associated with the substrate surface symmetry. The formation of rotational domains currently represents a major research challenge, as their presence severely degrades the structural, thermal, and transport properties of heteroepitaxial Ga₂O₃ layers and prevents the full exploitation of the material’s potential in power electronic devices.
Epitaxial growth will be carried out using a commercial Aixtron MOCVD growth system with a vertical CCS reactor, as well as an experimental MOCVD reactor employing liquid precursor injection. Furthermore, advanced technological equipment and processes available at the Institute of Electrical Engineering of the Slovak Academy of Sciences (IEE SAS), will be used. PhD candidate will acquire a broad range of experimental skills in materials diagnostics (e.g., X-ray diffraction, atomic force microscopy, Raman spectroscopy, and advanced electrical characterization methods). The work will be conducted within a joint collaboration project with the Taiwanese partner ITRI (Industrial Technology Research Institute).
Topic: Fabrication and characterization of Ga₂O₃-based rectifying diodes for high-voltage applications
Supervisor: : Ing. Filip Gucmann, PhD. (Department of III-V Semiconductors)
Co-advisor: RNDr. Dagmar Gregušová, DrSc.
Description: Gallium oxide (Ga₂O₃) is a novel ultra-wide-bandgap semiconductor material with a bandgap energy (Eg) of approximately 5 eV and a theoretical critical breakdown field (Ecr) exceeding 8 MV/cm, which makes it highly suitable for high-power and high-voltage rectifying and switching applications. Devices based on monoclinic β-Ga₂O₃ have the potential to significantly extend the capabilities of currently established semiconductors such as GaN and SiC and to enable reliable operation at voltages >6 kV, where suitable alternative is currently unavailable. Such devices are expected to find applications in high-efficiency power conversion systems, for example in fast battery chargers for electromobility, renewable energy sources (solar, wind), as well as in the defence sector.
This work will focus on the optimization of fabrication technology for Schottky-barrier diodes in vertical and semi-vertical configurations, as well as on a detailed study of transport mechanisms and degradation processes in these devices. The Ga₂O₃ semiconductor material will be grown by MOCVD at the Institute of Electrical Engineering of the Slovak Academy of Sciences (IEE SAS), v. v. i., on various substrates (Ga₂O₃, SiC, Si, sapphire), enabling the investigation of self-heating effects. The research will also include an investigation of the impact of various edge termination and protection structures (field plates, guard rings, etc.) on the reverse breakdown voltage of the diodes. The devices will be fabricated using advanced photolithographic processes and other technologies available at IEE SAS, in collaboration with the Taiwan Industrial Technology Research Institute (ITRI).
Physics of Condensed Matter and Acoustics
Topic: Study and optimization of detectors of ionizing radiation based on wide bandgap semiconductors as a SiC and diamond
Supervisor: Mgr. Bohumír Zaťko, PhD. (Department of microelectronics and sensors)
Description: The aim of the thesis is the technological preparation of ionizing detectors, the study of electrical and detection properties and the influence of radiation dose on their performance. The detection materials used are high quality epitaxial layers of 4H-SiC, polycrystalline and monocrystalline diamond layers. The work will initially focus on the design and fabrication of detection structures based on Schottky contacts. This will be followed by electrical characterization (current-voltage, capacitance-voltage measurements at different temperatures). SiC and diamond are wide bandgap materials that can operate at elevated temperatures. Selected suitable detection structures will be connected to a low noise spectrometric setup and their properties for particle detection at room and elevated temperatures will be evaluated. Subsequent structures will be irradiated with high doses of electron, proton or neutron-based radiation and their properties after irradiation will be investigated. Finally, the radiation hardness will be evaluated and compared with standard silicon detectors.
The work will be carried out at the Institute of Electrical Engineering Slovak Academy of Sciences, which has modern technological equipment necessary for the preparation and testing of various types of semiconductor structures. The PhD student will acquire knowledge in the preparation of semiconductor detector structures and will be actively involved in teamwork within national and international projects dealing with the preparation and testing of radiation detector structures.
Topic: Electrical transport in thin layers of some TMDC materials
Supervisor: RNDr. Martin Hulman, PhD. (Department of Physics and Technol. at Nanoscale)
Description: In the past two decades, materials characterized by significant dimensional anisotropy have become one of the most extensively studied subjects in solid-state physics and materials research. This category encompasses transition metal dichalcogenides (TMDCs), compounds composed of elements such as S, Se, and Te, in conjunction with metals like Mo, W, and Pt. Substances with the chemical formula MX2 can be synthesized in extremely thin layers.
At the Institute of Electrical Engineering, a team is dedicated to preparing thin layers of TMDC materials and conducting their characterization. The proposed dissertation would complement the endeavors of this group. The focus of the dissertation lies in examining the electrical transport properties of (ultra)thin layers of TMDC materials, particularly those within the subgroup exhibiting semi-metallic and metallic characteristics. The work predominantly entails experimental research. While it entails some involvement in the growth of thin layers, the primary emphasis is on measuring transport characteristics. In addition to transport characterization, the dissertation will explore the impact of temperature, doping, and structure on the conductivity of 2D materials.
Throughout the dissertation, the student will engage with vacuum and low-temperature facilities. The experimental findings will be analyzed in accordance with various models of solid-state physics. Furthermore, the student is expected to present their results at both domestic and international conferences, necessitating proficient spoken and written English skills.
Topic: Fabrication and characterization of Ga₂O₃-based rectifying diodes for high-voltage applications
Supervisor: : Ing. Filip Gucmann, PhD. (Department of III-V Semiconductors)
Co-advisor: RNDr. Dagmar Gregušová, DrSc.
Description: Gallium oxide (Ga₂O₃) is a novel ultra-wide-bandgap semiconductor material with a bandgap energy (Eg) of approximately 5 eV and a theoretical critical breakdown field (Ecr) exceeding 8 MV/cm, which makes it highly suitable for high-power and high-voltage rectifying and switching applications. Devices based on monoclinic β-Ga₂O₃ have the potential to significantly extend the capabilities of currently established semiconductors such as GaN and SiC and to enable reliable operation at voltages >6 kV, where suitable alternative is currently unavailable. Such devices are expected to find applications in high-efficiency power conversion systems, for example in fast battery chargers for electromobility, renewable energy sources (solar, wind), as well as in the defence sector.
This work will focus on the optimization of fabrication technology for Schottky-barrier diodes in vertical and semi-vertical configurations, as well as on a detailed study of transport mechanisms and degradation processes in these devices. The Ga₂O₃ semiconductor material will be grown by MOCVD at the Institute of Electrical Engineering of the Slovak Academy of Sciences (IEE SAS), v. v. i., on various substrates (Ga₂O₃, SiC, Si, sapphire), enabling the investigation of self-heating effects. The research will also include an investigation of the impact of various edge termination and protection structures (field plates, guard rings, etc.) on the reverse breakdown voltage of the diodes. The devices will be fabricated using advanced photolithographic processes and other technologies available at IEE SAS, in collaboration with the Taiwan Industrial Technology Research Institute (ITRI).