Full-time study

4 years

prof. RNDr. Tomáš Šikola, CSc.

Chairman :
prof. RNDr. Tomáš Šikola, CSc.
Councillor internal :
prof. RNDr. Petr Dub, CSc.
prof. RNDr. Radim Chmelík, Ph.D.
prof. Ing. Ivan Křupka, Ph.D.
prof. RNDr. Pavel Šandera, CSc.
Councillor external :
RNDr. Antonín Fejfar, CSc.
prof. Mgr. Dominik Munzar, Dr.
prof. RNDr. Pavel Zemánek, Ph.D.

The aim of the doctoral study in the proposed programme is to prepare highly educated experts in the field of physical engineering and nanotechnology with sufficient foreign experience, who will be able to perform independent creative, scientific and research activities in academia or applications in our country and abroad. The study is based on the doctoral students' own creative and research work at the level standardly required at foreign workplaces in the areas of research carried out at the training workplace and supported by national and international projects. These are the following areas of applied physics: physics of surfaces and nanostructures, light and particle optics and microscopy, construction of physical instruments and equipment, micromechanics of materials.

The graduate has knowledge, skills and competencies for their own creative activities in some of the areas in which the research activities of the training workplace are carried out. These are applications of physics especially in the field of physics of surfaces and nanostructures, two-dimensional materials, nanoelectronics, nanophotonics, micromagnetism and spintronics, biophotonics, advanced light microscopy and spectroscopy, electron microscopy, laser nanometrology and spectroscopy, computer controlled X-ray micro and nanotomography, micro and development of technological and analytical equipment and methods for micro/nanotechnologies. The possibility of using the personnel and material background provided by the CEITEC research infrastructure as well as extensive cooperation with important foreign workplaces contributes to the high level of education. This guarantees that the graduate is able to present the results of their work orally and in writing and discuss them in English. Due to high professional competencies and flexibility, graduates find employment both in universities and other research institutions in our country and abroad, and in high-tech companies in the positions of researchers, developers, designers or team leaders.

Due to their high professional competencies and flexibility, graduates find employment in the field of basic and applied research at universities and other research institutions in our country and abroad, as well as in high-tech companies in the positions of researchers, developers, designers and team leaders.

See applicable regulations, DEAN’S GUIDELINE Rules for the organization of studies at FME (supplement to BUT Study and Examination Rules)

The rules and conditions of study programmes are determined by:
BUT STUDY AND EXAMINATION RULES
BUT STUDY PROGRAMME STANDARDS,
STUDY AND EXAMINATION RULES of Brno University of Technology (USING "ECTS"),
DEAN’S GUIDELINE Rules for the organization of studies at FME (supplement to BUT Study and Examination Rules)
DEAN´S GUIDELINE Rules of Procedure of Doctoral Board of FME Study Programmes
Students in doctoral programmes do not follow the credit system. The grades “Passed” and “Failed” are used to grade examinations, doctoral state examination is graded “Passed” or “Failed”.

Brno University of Technology acknowledges the need for equal access to higher education. There is no direct or indirect discrimination during the admission procedure or the study period. Students with specific educational needs (learning disabilities, physical and sensory handicap, chronic somatic diseases, autism spectrum disorders, impaired communication abilities, mental illness) can find help and counselling at Lifelong Learning Institute of Brno University of Technology. This issue is dealt with in detail in Rector's Guideline No. 11/2017 "Applicants and Students with Specific Needs at BUT". Furthermore, in Rector's Guideline No 71/2017 "Accommodation and Social Scholarship“ students can find information on a system of social scholarships.

The presented doctoral study programme represents the highest level of education in the field of physical engineering and nanotechnology. Follows the academic and bachelor's and subsequent master's degree programme of "Physical Engineering and Nanotechnology", which are carried out at FME BUT.

1. Advanced imaging techniques in electron microscopy

   The aim of the dissertation thesis is instrumental and methodological development in the field of scanning electron microscopy (SEM), which will include mainly 4D-STEM imaging of beam sensitive samples using a 2D direct electron detector. Part of the work will be the development of a methodology for the preparation and imaging of samples sensitive to electron and ion beam irradiation. Designs of new procedures for the processing of measured 4D data will be created which will contribute to the development of modern diffractive techniques in electron microscopy. These methods will be applied primarily to biological samples and their combinations with nanoparticles, which play an important role in medicine, pharmacology etc. The project will take place at the Institute of Scientific Instruments (ISI) of the Czech Academy of Sciences with possibilities of a partial/full-time job. PhD student will participate in several TAČR and GAČR projects, which are currently being solved at ISI.

   Tutor: Krzyžánek Vladislav, Ing., Ph.D.

2. Advanced scanning probe microscopy of functional materials and nanostructures

   This work will deal with the characterization and preparation of advanced materials and nanostructures by scanning probe microscopy (SPM) combined with scanning electron microscopy (SEM), measuring their physical properties (e.g., cathodoluminescence, optical properties) in order to correlate these measurements with surface morphology (CPEM). This study will include the development of advanced SPM probes of a new generation, which will be used for in situ modification of sample properties (e.g., by applied voltage, incident light or applied working medium near the sample’s surface) or for the preparation of nanostructures itselfs.

   Tutor: Spousta Jiří, prof. RNDr., Ph.D.

3. All-dielectric Metasurfaces

   Metasurfaces represent a new kind of promising nanophotonic devices providing new functionalities at their radical miniaturization. Thus, they are perspective for outperforming classical optical elements and devices. They consist of subwavelength nanoelements, either metallic or dielectric, which contribute to forming their overall optical properties by scattering-induced phase modification. Plasmonic metasurfaces, i.e. those based on metallic elements, are generally lagging behind the expectation because of big ohmic losses in their metallic constituents. Therefore, PhD study will be aimed at exploring all-dielectric metasurfaces utilizing Mie resonances [1] and providing novel functionalities concerning modification of optical properties and shaping optical beams. Here, a special attention will be paid to (i) tunable systems with overlapping magnetic and electric dipole resonances which might lead e.g. simultaneously to EIT and enhanced Faraday rotation [2] and other interesting effects. Such tuned systems might act as sensitive sensors to their surroundings, e.g. magnetic molecules, and to (ii) tunable chiro-optical surfaces [3]. The optical properties of metasurfaces and beams shaped by them will be studied by (i) far-field illumination and detection methods. In addition to standard methods like transmission/reflection micro-spectroscopy, we will use an original method of quantitative phase imaging by coherence-controlled holographic microscopy (CCHM) [4] and follow-up Q4GOM microscopy [5]. By this wide-field technique, we introduced into the area of metasurfaces, the phase of radiation scattered/shaped by resonators/metasurfaces can be quantitatively imaged over the whole sample area/beam in-real time with resolution down to a single antenna. Further, (ii) far-field illumination and near-field detection approach will be used using a spectroscopic a-SNOM [6]. References: [1] Dielectric Metamaterials: Fundamental, designs, and applications, ed. by I. Brener et al., Elseviere – Woodhead publishing series, 2020. [2] A. Christophi, …, A. B. Khanikaev, Opt. Lett. 43, 8, 2018. [3] I. Zubritskaya, …, A. Dmitriev, Nano Lett. 18, 302−307, 2018. [4] J. Babocký, V. Křápek, ..., T. Šikola, ACS Photonics 4, 1389, 2017. [5] P. Bouchal, P. Dvořák, F. Ligmajer, M. Hrtoň, V. Křápek, ..., T. Šikola, Nano Lett. 19, 1242, 2019. [6] P. Dvořák, ..., T. Šikola, Nano Lett. 13, 2558, 2013.

   Tutor: Šikola Tomáš, prof. RNDr., CSc.

4. Application of KPFM in graphene based sensors and solar cells

   Kelvin's probe force microscopy (KPFM) is an excellent tool for mapping the distribution of surface potential locally up to nanometer resolution. This can be advantageously used in a study of charge distribution on nanometer-sized sensors and at investigation of p-n interfaces of solar cells during their operation. This new information, in addition to commonly studied sensor current responses and solar cell voltage responses, makes it easier to understand the ongoing physical processes, use this knowledge to eliminate the shortcomings of existing devices, and possibly to design higher efficiency devices. At work, you will need to master the general physical principles of KPFM, sensors and solar cells. A suitable applicant is a graduate of a Master's degree in Physics, Electrical Engineering or Chemistry. Aims: 1) Mastering physical principles and measurement of graphene-based sensors and solar cells. 2) Adopting theoretical and practical aspects of KPFM. 3) Mapping the charge distribution close to a graphene sensor and designing more sophisticated sensors. 4) Mapping the potential distribution on the graphene-semiconductor solar cell interface and designing the cell with higher efficiency. 5) Adequate publishing outputs and presentation of results at international conferences.

   Tutor: Bartošík Miroslav, doc. Ing., Ph.D.

5. Cutting-edge techniques for preparation of cross sections of advanced materials for SEM imaging

   Scanning electron microscopy observation of a specimen cross-section can provide important information for material research and development as well as failure analysis. Typically, a cross-section is prepared using mechanical means like conventional mechanical polishing methods or a microtome. Such methods can be lengthy procedures that require a great deal of skill and can introduce artifacts into soft materials, deform the material around voids, or compress layers of soft and hard materials in composite samples. A Focused Ion Beam (FIB) system is used when precise positioning of the cross-section is required, such as in the case of thin-film or micro area specimen preparation. However, the size of the resulting cross-section is limited, and the heavy gallium ions in the beam can damage the sample surface. A plasma FIB provides an effective solution to prepare large-area cross-sections but this technique is not suitable for sensitive materials. Modern Ar ion beam cross-section polisher simplifies the preparation of samples and makes it possible to prepare truly representative cross-sections of samples almost free of artifacts and distortion. The use of the broad Ar ion beam eliminates the problems associated with conventional polishing and allows for larger specimens to be prepared with precision. On the other hand, establishing the optimal process parameters for artifacts-free polishing is not trivial. Preparation of cross-sectional samples by an ultramicrotomy, laser beam, or water jet cutter is less known but can also provide interesting results. The thesis will provide a comprehensive review of standard and advanced cross-section methods. The goals of the thesis are the experimental comparison of the above-mentioned techniques for cross-sectional sample preparation, discuss their pros and cons, and elucidate the mechanism of sample damage using these techniques. The specimens will be characterized by advanced electron microscopy techniques, including a low voltage STEM with atomic resolution.

   Tutor: Mikmeková Šárka, Ing. Mgr., Ph.D.

6. Development of a tomographic module for a Coherence Controlled Holographic Microscope

   The aim of this work is to design a tomographic module for a new version of the Coherence Controlled Holographic Microscope. The design must be based on an optical simulation, from which the construction of the module and its control will be derived. It is also necessary to create control software for the module.

   Tutor: Chmelík Radim, prof. RNDr., Ph.D.

7. Development of opto-mechanical system for in-situ analysis using laser-induced breakdown spectroscopy

   Laser-Induced Breakdown Spectroscopy (LIBS) as a method of analytical chemistry excells in direct use for in-situ analysis of samples. This benefit is vitally used in many applications, in this case, the aim is set to plastic industry. Robustness and universality of LIBS instrumentation is ballanced by non-existing or limited accessibility to commercially available solutions. Thus, development of LIBS instrumentation and optimization of analytical methodology is closely interconnected and will be the topic of this dissertation thesis. The goal is the design of optomechanical parts of a LIBS system and its construction with respect to the trade-off between sensitivity and repetition rate. Furthermore, the development of related methodology for accurate classification of polymers and quantitative analysis of trace toxic metals.

   Tutor: Pořízka Pavel, doc. Ing., Ph.D.

8. Development of robotic components for a Coherence Controlled Holographic Microscope

   The aim of this work is to design robotic components for a new version of the Coherence Controlled Holographic Microscope. The design must be based on the principles of automatic adjustment and manipulation of samples, from which the construction of components and their control will be derived.

   Tutor: Dostál Zbyněk, Ing., Ph.D.

9. DFT calculations of graphene and related 2D materials with regard to application in senors / biosensors

   Due to its biocompatibility, high mobility of charge carriers and ultra-sensitivity of electronic properties to the presence of individual adsorbed and substituted atoms and molecules, graphene is a suitable material for utilization in the area of sensors and biosensors. Density functional theory (DFT) allows first-principle determination of the adsorbents and substitutes influence on the electronic properties of graphene and other 2D materials, which are key for understanding the physical nature of these devices operation. The subject of this doctoral thesis is the study of this issue using DFT calculations in a broader theoretical context, as well as computational support for experiments performed within the group. Therefore, the person with strong theoretical background in quantum mechanics, solid state physics, and practical knowledge of DFT calculation and data processing is expected.

   Tutor: Bartošík Miroslav, doc. Ing., Ph.D.

10. Electron gun for Ultra Fast TEM

    Ultra Fast TEM (U-TEM) allows to monitor dynamic phenomena such as phase changes, melting/crystallization of materials with time resolution in ns to ps. Furthermore, samples sensitive to electron beam exposure can be observed using stroboscopic illumination (another U-TEM mode). Current U-TEM microscopes use photoemission sources or a combination of standard sources with very fast deflectors (RF cavity,…). Nanostructured materials appear to be very promising for the production of U-TEM electron sources. For example, GaN materials are seems to be good candidate for this purpose due to their considerable chemical and thermal resistence, low switching voltage of 1.25 V/um and high current density. The properties of the cathode depend to a large extent on the shape and form of nanostructures such as nanotubes, nanocarbons and nanocrystals.

    Tutor: Zlámal Jakub, Ing., Ph.D.

11. Electron tweezers and development of new applications

    The dissertation will deal with the development of electron tweezers, which allows to move droplets of eutectic liquids on the surface of semiconductors. The electron tweezers utilize the focused electron beam and is already tested in the UHV-SEM microscope, developed in cooperation with TESCAN company. During the controlled movement, the gold-containing droplet can for example etch or otherwise modify the surface of semiconductors (germanium, silicon). The dissertation thesis should focus on the interaction of different eutectic droplets with various substrates including 2D materials (graphene, etc.). Part of this work will be optimization of this process including its real-time monitoring using UHV-SEM microscope.

    Tutor: Průša Stanislav, doc. Ing., Ph.D.

12. GaN/Graphene-based detectors of UV radiation

    The PhD project will concentrate on a study of complex issues related to development of UV detectors using GaN (Ga)/graphene nanostructures. The initial part of the study will focuses on the preparation of Ga and GaN nanostructures on poly-and single-crystal graphene using a low-temperature deposition method. The low temperature growth of GaN nanocrystals will be carried out by a combination of UHV PVD technologies such as Ga vapour deposition and low energy nitrogen ion-beam (50 eV) post-nitridation using a unique ion-atomic beam source [1] . The growth of GaN will be realized at much lower temperatures (T<250°C) than in conventional technologies (e.g. MOCVD, 1000°C). Subsequently, the relation between parameters/functional properties of Ga and GaN nanostructures and deposition conditions will be studied. The complex characterization of the Ga (GaN)/graphene nanostructures will be provided by Scanning Electron Microscopy (SEM), Scanning Probe Microscopy (AFM, EFM, SKFM), Raman spectroscopy, photoluminescence micro-spectroscopy, etc. Finally, the electrical response of the nanostructures to UV radiation will be studied via a FET-setup utilizing these optimized nanostructures as photosensitive elements. References: [1] J. Mach, P. Procházka, M. Bartošík, D. Nezval, J. Piastek, J. Hulva, V. Švarc, M. Konečný, and T. Šikola, Nanotechnology, Vol. 28, N. 41 (2017).

    Tutor: Šikola Tomáš, prof. RNDr., CSc.

13. Generation and detection of THz spin waves by plasmonic antennas

    Spin waves in the THz region have become a subject of growing interest due to a high group velocity of magnons (steep dispersion curve) which renders them attractive for the design of ultrafast spintronic devices [1]. Here, antiferromagnetic materials like rare earth orthoferrites (RFeO3) could be a solution because of their very high (terahertz) frequencies of spin resonances [2], [3]. However, due to the lack of efficient sources and detectors, the physics of magnons at THz frequencies is far less studied. The proposed interdisciplinary PhD study combining photonics and magnetism is based on generation and detection of THz spin waves by near fields enhanced by plasmonic resonant structures - antennas. It brings a new qualitative view into this subject. The antennas will be fabricated on a substrate surface, ideally on ribbons or magnonic crystals made out of RFeO3 thin film samples (e.g. TmFeO3) by EBL/FIB at CEITEC. Then, the magnons propagating along these structures will be analysed by a Brillouin light scattering (BLS) micro-spectrophotometer [4], using the method reported in [5] and successfully implemented at CEITEC [6]. Further, to extend the detected Brillouin-zone range, plasmonic resonant nanostructures providing large momentum components in their near-field hot spots will be used as well [7]. In this PhD study, plasmonic resonant structures for generation and detection of magnons should be optimized, and then dispersion relations tuned by shape, dimensions and periodicity of ribbons/magnonic crystals [6] and external magnetic field. Supportively, magnetic near-field enhanced THz T-D spectroscopy might be applied to test magnon-polariton dispersion curves of the thin film samples according to [3]. References: [44] K. Zakeri, PHYSICA C 549, 164, 2018. [45] J. Guo, J. Phys.: Condens. Matter 32, 185401, 2020. [41] K. Grishunin, ACS Photonics 5, 1375, 2018. [46] T. Sebastian, …, H. Schultheiss, Front. Phys. 3, 35, 2015. [47] K. Vogt, …, B. Hillebrands, Appl. Phys. Lett. 95, 182508, 2009. [38] L. Flajšman, …, M. Urbánek, Phys. Rev. B 101, 014436, 2020. [X] R. Freeman,,…., Phys. Rev. Research 2, 033427 (2020).

    Tutor: Šikola Tomáš, prof. RNDr., CSc.

14. In-situ microscopy and spectroscopy of 2D materials growth

    The observation of 2D materials growth at nanoscale is a challenging task. In our group, we have a large expertise in real time electron microscopy and we operate beyond-state-of-the-art instrumentation (LEEM, FTIR in UHV and SEM for observations in extreme conditions). The aim of this PhD dissertation is to revealing the growth modes of 2D materials (transitiv metal dichalcogenides, group-IV-based 2D materials etc.) and thein properties by advanced microscopy and spectroscopy in UHV as well as under high pressure and at high temperature.

    Tutor: Kolíbal Miroslav, prof. doc. Ing., Ph.D.

15. In-situ preparation and modification of nanostructures

    Revealing the growth mechanisms at nanoscale is particularly challenging from many reasons. The most prominent advances in physics of nanostructure growth were achieved utilizing real-time in-situ monitoring techniques (both microscopic and spectroscopic). In our group, we have a large expertise in real time electron microscopy and, this year, a new vacuum chamber dedicated to Fourier transform Infrared spectroscopy was installed to CEITEC Nano infractructure. The aim of this PhD dissertation is to work on revealing puzzling growth modes of twodimensional nanostructures of interest (silicene, phosphorene, transition metal selenides etc.) utilizing state-of-the-art equipment, as well as study of their interaction with electrons, and oxidation.

    Tutor: Kolíbal Miroslav, prof. doc. Ing., Ph.D.

16. Mapping plasmonic modes

    Localized surface plasmons (LSP) generated in metal nanoparticles (plasmonic antennas) can exhibit various modes differing in energy, charge distribution (dipoles vs. multipoles) and radiation capability (bright and dark modes). One of the most effective methods enabling generation and characterization - mapping of these modes at the single antenna level is Electron Energy Loss Spectroscopy (EELS) provided by High-resolution Scanning Transmission Electron Microscopy (HR STEM). The PhD study will be aimed at application of HR STEM-EELS for mapping the modes of LSP in plasmonic antennas. The emphasis will be especially put at a study of hybridized modes of coupled antenna structures and/or strong coupling effects between modes in plasmonic antennas and excitations in their surrounding environments. These excitations will be polaritons in quantum nanodots localized nearby antennas (the visible range) and/or phonons in absorbing antenna substrate membranes (IR – mid IR). In the former case, the experiment will be carried out by HR STEM-EELS at CEITEC Nano infrastructure (Titan), in the latter case, by Nion Ultra STEM available at some laboratories abroad (e.g. Oak Ridge national laboratory).

    Tutor: Šikola Tomáš, prof. RNDr., CSc.

17. Micro machining of photonic structures with a femto second pulsed laser.

    Fs pulsed laser micro machining is a very powerful technology for the creation of photonic structures. It is a maskless technology that is capable of rapid prototyping of 3D objects and can produce complex microsystems with advanced features. It makes the production of three-dimensional photonic microsystems much easier than electron lithography. In the field of micro optics, this is a very promising technology that enables innovative applications. It is very easy to convert technology from subtractive to additive by using polymers. And as one of the few technologies, it is capable of creating waveguides directly in the volume of an optical element. The aim of the dissertation will be the development of a workstation containing systems for progressive laser beam shaping, which by spatial and temporal modification fs laser beam will enable the generation of 3D photonic structures with focusing on refractive and reflective optics at high speed with details below the diffraction limit. An integral part of the work will be the necessary physical and technical background of the device design, optical design of devices and micro structures, measurement of optical parameters of manufactured photonic structures.

    Tutor: Šerý Mojmír, Ing., Ph.D.

18. Microscopy with geometric-phase optical elements

    Geometric-phase optical elements are a new tool for complex light shaping and generation of special states of light. Unlike traditional refractive elements, the geometric-phase elements control the light using transformation of its polarization state. Thanks to technology of liquid crystals or principles of plasmonics, geometric-phase elements provide abrupt phase changes on physically thin substrates. Compact size and unique polarization properties make them ideal candidates for simply integrable spatial light modulators. The dissertation thesis topic is to find and verify the potential of geometric-phase elements in common-path digital holography and advanced optical microscopy.

    Tutor: Chmelík Radim, prof. RNDr., Ph.D.

19. Modeling of functional properties of nanostructures for plasmonics

    For detailed info please contact the supervisor.

    Tutor: Kalousek Radek, doc. Ing., Ph.D.

20. Multi-modal minimally invasive holographic endoscope for deep brain imaging

    The methods of holographic endoscopy have recently emerged as a powerful platform to introduce sub-cellular resolution microscopy deep inside tissues of living organisms, including brain. Our laboratory of Complex Photonics (lead by Prof. Čižmár) has been developing cutting edge multi-mode fibre based endoscopes and applying them in brain imaging in animal models in vivo. These minimally-invasive endoscopes can reach deep subcortical locations in the brain which are not accessible by other optical methods of similar resolution. This PhD work will focus on expanding the capabilities of the system with two new modalities: optical manipulation of cells using optogenetics and extracellular electrophysiological recordings. Optogenetics is a unique tool that enables manipulation of cellular activity with light. Electrophysiology has been a golden standard method of neuroscience for the past fifty years which allows recordings of local field potentials (LFP) and multi-unit activity (MUA) of neurons. Uniquely, these modalities will be implemented within the same thin endoscopic probe which serves for imaging. Implementation of electrophysiology will be carried out in collaboration with Prof. Massimo de Vittorio and Dr. Ferruccio Pisanello (Instituto Italiano de Technologia). The candidate will develop/modify optical setups and the software for hardware control and data acquisition and processing (Lab View, Matlab, C++). Knowledge and experience in programing, optical set-up building, microscopy, fluorescence microscopy or electrophysiology is desirable. The work will be carried out at the Institute of Scientific Instruments of the Academy of Sciences of the Czech Republic with the possibility of full-time employment. The PhD student will be a part of a European Commision project “DEEPER: Deep brain photonic tools for cell-type specific targeting of neural diseases", which is funded within the European Union’s Horizon 2020 research and innovation actions scheme as is just starting at this institute. This Consortium clusters world-leading experts in molecular photonic tools, optical technology, pre-clinical, clinical brain research and innovative start-ups in an endeavour of providing new tools to tackle the mechanisms underlying the pathogenesis of neurological disease.

    Tutor: Čižmár Tomáš, prof. Mgr., Ph.D.

21. Novel effects in guided-wave nanophotonics structures

    The theoretical analysis of novel optical effects and functionalities in modern nanophotonic guided-wave structures is impossible without adequate and powerful numerical tools. The project will focus on development and application of such techniques that are based on eigemode expansion. Application will address selected interesting problems, such as, nanophotonics arrays that support the bound states in continuum, the issues related to the loss compensation in plasmonic structures, systems with gain and loss where realistic models of gain media based on the rate equations for the populations is used, and modulation in hybrid waveguides with graphene.

    Tutor: Petráček Jiří, prof. RNDr., Dr.

22. Numerical processing methods of experimental data for imaging spectroscopic reflectometry within the framework of the optical characterization of thin solid films

    The content of the dissertation thesis is to find effective algorithms for numerical processing of big sets of experimental data obtained by means of imaging spectroscopic Reflectometer (built in The Coherence Optics Laboratory of IPE FME BUT) from non-uniform thin films for the determination of the optical parameters of these films. The goal is to realize aforementioned algorithms in the form of a software.

    Tutor: Ohlídal Miloslav, prof. RNDr., CSc.

23. Optical characterization of advanced materials and nanostructures

    Due to their dimensions comparable with the wavelength of light, nanostructures can directly modify properties of reflected and/or transmitted electromagnetic waves. The discipline investigating the interaction of an electromagnetic wave and nanostructures is called Nanophotonics. Its applications can be found for instance in photovoltaics or enhanced optical spectroscopy. Besides the shape and dimensions of nanostructures, the light can be also modified by their material properties. Recently, many scientific teams have been concentrating on the optically active advanced materials such as perovskites or 2D transition metal dichalcogenides (TMDs). These advanced materials can be often characterized by their photoluminescence, especially using confocal optical spectroscopy, time-resolved spectroscopy, or scanning near-field optical microscopy. All these experimental techniques together with adequate numerical simulations (e.g., FDTD, DFT, BEM) are available at the Institute of Physical Engineering BUT and will constitute the main tools for successful completion of the PhD research project.

    Tutor: Kalousek Radek, doc. Ing., Ph.D.

24. Phase-change material nanophotonics

    Nanophotonics embodies all sorts of specifically nanostructured surfaces that enable control of light propagation, acting as both free-space or integrated optical components. Introducing phase-change materials into nanophotonic devices brings in the possibility to tune or switch their properties and change them into active optical components. This dissertation will be focused on incorporation of phase change materials (such as VO2, Sb2S3 or Ge2Sb2Te5) into various nanophotonic devices with the main goal of optical control of the resulting tunable optical components.

    Tutor: Šikola Tomáš, prof. RNDr., CSc.

25. Physical modelling of turbulent Rayleigh-Bénard convection under rotation

    Rotating Rayleigh-Bénard convection (RBC) represents a universally recognized physical model used to study flows affected by rotation and thermal forcing. Physical systems with dynamics strongly influenced by these forces include the interiors of giant planets and rapidly rotating stars, the Earth’s outer liquid core, as well as open ocean deep convection. The rotation induces different regimes in RBC, which are reflected in the heat transfer efficiency (via Nusselt number) and flow field morphology (shape of large coherent structures) distinct from the non-rotating RBC. Within the Oberbeck- Boussinesq approximation the dynamics of RBC with a constant rotation rate angular velocity is described by the three dimensionless control parameters, namely, the Rayleigh number Ra, Prandtl number Pr and the Ekman number Ek. Small values of Ek, the ratio of viscous and Coriolis forces, correspond to high rotation rates angular velocities. In the large scale geophysical and astrophysical systems like the Earth or the Sun, these control parameters reach extreme values; for example, in the Earth’s outer core, their estimated values are Ra∼1E20–1E30 and Ek∼1E-15. The current limits of direct numerical simulations of rotating RBC are restricted to ranges of Ra <~ 1E7 and Ek >~ 1E−6. The PhD study will be focused on experimental study of rotating RBC at very high values of these control parameters in Laboratory of the Cryogenics and superconductivity group of the Institute of Scientific Instruments CAS. The laboratory is equipped with a unique RBC apparatus with rotating platform, using cryogenic helium gas (5 K) as a working fluid, allowing to rich the control parameters values 10-8 < Ek < 10-5 and 1E6 < Ra < 1E15. The student is invited to join our team and collaborate on this basic research supported by co-operative GACR project (20-00918S) with the group of prof. L. Skrbek (MFF UK)

    Tutor: Urban Pavel, Ing., Ph.D.

26. Synthesis and Characterization of Band Gap Engineered Ferroelectric Oxides for Photovoltaics

    The direct conversion of sunlight into electricity is a very elegant method to produce environmentally friendly renewable energy. This branch of science is known as "photovoltaics (PVs)." Recently ferroelectric (FE) solar cells have become very popular among various research groups all over the world due to their unique features such as having open circuit voltages (VOC) higher than their band gaps, and holding spontaneous polarization, which leads to a photovoltaic (PV) effect. The current problems with the present FE PV materials is that i) wide band gap (Eg), which is close to 3 eV for the most of FE PVs, ii) poor sunlight absorption, iii) short lifetime of the generated charge carriers and iv) the low mobility of charge carriers. The present PhD study aims at: i) reducing the band gap of targeted FE materials usually having band gaps between 2 and 4 eV via doping. ii) Hybridizing organic singlet exciton fission (SF) materials with inorganic FE materials to synthesize epitaxial FE photovoltaic (PV) films. iii) Investigating the electrical and optical properties of obtained FE-PVs. iv) Understanding the mechanism behind the solar energy conversion in FE PV devices. FE PV thin films will be grown by using physical vapor deposition processes, for instance, magnetron sputtering, pulsed laser deposition and molecular beam epitaxy. The obtained films will be characterized by X-ray diffraction method, X-ray Photo-electron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), and HR (S)TEM and so on. Furthermore, the optical and electrical properties of the materials will be examined.

    Tutor: Šikola Tomáš, prof. RNDr., CSc.

27. Topological Insulators and Topological Superconductors

    Topological insulators (TIs), which demonstrate conductor properties at surfaces and behave as insulator in the bulk, present unique quantum state properties. Therefore, we have witnessed enormous research interest on these materials. It is anticipated that TI materials have a great potential to serve as a platform for spintronics due to their spin-locked electronic states, which could open new avenues for spintronic, quantum computing and magnetoelectric device applications. Moreover, interfacing TIs with superconducting layers is predicted to create mysterious physical phenomena, ranging from induced magnetic monopoles to Majorana fermions. The present PhD study aims at i) synthesizing theoretically studied topological insulators and ii) investigating topological superconductors, formed by hybridizing TIs and superconductor materials. TI and superconductor thin films will be fabricated via employing physical vapor deposition processes such as magnetron sputtering, pulsed laser deposition and molecular beam epitaxy. The obtained films will be characterized by X-ray diffraction method, X-ray Photo-electron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), and HR (S)TEM and so on. Furthermore, the magnetic properties of the thin films will be examined by Vibrating Sample Magnetometer (VSM). In addition, magneto-transport measurements of these films will be carried out as well.

    Tutor: Šikola Tomáš, prof. RNDr., CSc.

28. Topological insulators studied by LEIS

    The Low Energy Ion Scattering (LEIS) has proved its capability to study composition of the solid state surfaces. The extreme surface sensitivity of the technique is widely used in analysis of the elemental composition of a topmost atomic layer. The topological insulators are materials where the thin surface layer is conductive in two directions parallel to the surface plane while the bulk material remains insulating. These materials are very promising in the field of spintronics and quantum computation. Thus the surface termination plays the critical role in the definition of the topological insulator properties and can be effectively studied using LEIS in combination with selected analytical and imaging techniques (XPS, SIMS, SEM, AFM and STM). The state of art LEIS spectrometer (Qtac100, ION-TOF GmbH) is part of the complex UHV apparatus for deposition of thin films and modification of solid state surface at micro and nanotechnology laboratory of CEITEC BUT.

    Tutor: Průša Stanislav, doc. Ing., Ph.D.

29. Topological modes in photonics arrays and lattices

    Topology is the branch of mathematics concerned with quantities that are preserved under continuous deformations. The application of topology is revolutionizing photonics, bringing with it new theoretical discoveries and a wealth of potential applications. This field was inspired by the discovery of topological insulators, in which interfacial electrons transport without dissipation even in the presence of impurities. Similarly, we can design photonic lattices or coupled waveguide arrays supporting topologically protected states of light. According to the agreement, the work will focus on theoretical research of topological states in selected photonic structure, e.g., coupled nanoparticles or plasmonic waveguide arrays. The study assumes either the development of own methods or the use of commercial software (e.g. Lumerical, Comsol).

    Tutor: Petráček Jiří, prof. RNDr., Dr.

30. Transport Properties of 2D Materials

    The work will be devoted to a study of transport properties of 2D materials (graphene, transition metal dichalcogenides,….) modified by various layers of adsorbants. Emphasis will be put on in situ-measurements of these properties under well defined UHV conditions and consequently to their utilization in sensing and other applications.

    Tutor: Bartošík Miroslav, doc. Ing., Ph.D.

31. Utilization of plasmonic nanostructures for local enhancement of magnetic components of electromagnetic fields

    The study will be aimed at design, fabrication, and characterization of resonant plasmonic nano- and micro-structures (“diabolo” antennas, split ring resonators, etc.) providing a significant local enhancement of magnetic components of electromagnetic fields. The structures with resonant properties particularly in the IR and THz will be studied, with respect to their potential applications in relevant spectroscopic methods.

    Tutor: Šikola Tomáš, prof. RNDr., CSc.

32. 2D materials for supercapacitors

    Supercapacitors (SCs) represent one of the most promising energy storage technologies because of their remarkable features, such as ultrahigh power density and ultralong cycling life. This PhD study aims at an exploration of 2D hybrids based on MXenes and black phosphorous (BP), as high-performance electrode materials for SCs. It will concentrate on (i) multi-scale characterization of 2D hybrids up to atomic resolution to provide fundamental knowledge underlying the interaction between the components of 2D hybrids, and on (ii) an in situ study of chemical stability and growth mechanisms of these materials. In the study, state-of-the-art characterisation methods available at CEITEC Nano core facility such as Low Energy Electron Microscopy (LEEM), UHV STM/AFM, X-ray Photo-electron Spectroscopy (XPS), Low Energy Ion Scattering (LEIS), Scanning Auger Microscopy (SAM), FT-IR Spectroscopy, and HR (S)TEM will be used. The collaboration with the Dresden University of Technology planned to synthesize the 2D materials will be held.

    Tutor: Šikola Tomáš, prof. RNDr., CSc.

33. 3D epitaxial printing of semiconductors using electron tweezers

    The dissertation thesis will deal with the development of 3D epitaxial printing using eutectic liquid droplets, which are moved by electron beam (electron tweezers) in the UHV-SEM microscope, developed in cooperation with TESCAN. During the movement, the gold-containing droplet is saturated with germanium (silicon) atoms, resulting in epitaxial deposition of the semiconductor at the droplet location. The movement of the droplet and thus also the "print" location of the semiconductor can be controlled programmatically. Part of the work will be optimization of this process including its real-time monitoring using UHV-SEM microscope.

    Tutor: Průša Stanislav, doc. Ing., Ph.D.