Profile of the branch:|
The curriculum concentrates on the comprehensive study of materials properties and failure processes from the point of view of physics and physical metallurgy. Students should develop capability to apply their knowledge in inventive manner to new technologies and materials, such as plasma spraying, special methods of thermo-mechanical and thermo-chemical treatment, etc. Special attention is paid to the degradation processes and to the synergetic effects of various materials properties on material failure. The subjects of study are metallic and non-metallic materials, e.g., structural ceramics, polymers, amorphous and nanocrystalline materials and intermetallics.
The Ph.D. programme requires proficiency in mathematics and physics at the MSc. degree level obtained from Faculty of Science or Faculty of Mechanical Engineering.
Key learning outcomes:|
Occupational profiles of graduates with examples:|
Issued topics of Doctoral Study Program:|
- Application of Kelvin Probe Force Microscopy on Two-Dimensional Nanostructures
By using Kelvin Probe Force Microscopy (KPFM) information on local electronic properties (e. g. surface potential, work function) of two-dimensional nanostructures can be obtained. This information can be used for understanding of physical principles, design, sensitivity/effectivity improvement of solar cells and sensors based on the 2D nanostructures. In the project, the Kelvin Probe Force Microscopy will be used e. g. for study of p-n junction in solar cells and charge transport observation in sensors based on graphene.
- Correlative detection of signals in scanning electron microscopy
The aim of the dissertation thesis is instrumental and methodological development in imaging of samples using scanning electron microscopy (SEM) including correlation of signals from detectors of electrons (secondary, back-scattered) and photons (cathodoluminescence, X-ray). This research includes quantitative imaging for selected signals that will provide more detailed information about investigated samples and in turn precise comparison of the measured data with theoretical simulations. The correlation of different signals together with quantitative imaging extends the conventional imaging in SEM and adds value to images in the form of acquired physical and biophysical properties in investigated samples. Potential specimens for this imaging are mainly biological samples and their combinations with nanoparticles showing cathodoluminescence, which play important role in medicine, pharmacology etc.
- Cryogenic scanning electron microscopy (cryo-SEM) for study of hydrated samples
The aim of the dissertation thesis is instrumental and methodological development in cryogenic scanning electron microscopy (cryo-SEM). Significantly hydrated samples can be physically fixed (very quickly frozen) into amorphous ice just under certain conditions, where during the freezing process the crystallization does not have time to occur (typical limiting factors may be the temperature of cryogen, speed of freezing, the sample thickness, etc.). For these purposes, number of techniques were developed such as plunging into liquid ethane, propane-jet. So far the most sophisticated freezing technique is the use of the liquid nitrogen under high pressure (high-pressure-freezing; HPF). Thus, part of this work is development of a system based on freezing of small volumes using microfluidic chips that can extend cryo-EM techniques to in-situ experiments and could be the bridge between classical freezing techniques and HPF. Newly developed cryo-techniques will be further adapted to cryo-SEM method of freeze-fracture and consequently applied to biomedical samples.
- Diffraction contrast in STEM and application in measurement of electron microscope optical properties
Sample imaging in scanning transmission electron microscope (STEM) or transmission scanning electron microscope (TSEM) are standard microscopical techniques. But they can be also used for determination of aberration coefficients which is based on computer processing of amorphous sample images. The knowledge of the aberration coefficients is necessary for alignment of corrected electron microscopes.
The standard approaches are based on Ronchigram - shading image of the specimen measured on 2D pixel detector behind the sample. The aberration coefficients can be determined from one or low number of Ronchigrams. If the microscope is not equipped by this detector the aberration coefficients can be determined from form series of diffractograms - Fourier transformations of amorphous specimen images with different sample tilt.
The work will be concern on development and optimization of the method for system with 2D segmented detector behind the sample. It will cover design, simulations and experimental verification of the method.
- Fabrication and characterization of GaN nanostructures
Study of GaN nanostructures:
- fabrication of GaN nanostructures (ultratin films, nanocrystals and nanofibres) by atom/ion beams and other methods,
- characterization of composition and structure of GaN products,
- measurement of optical properties (potoluminiscence) of GaN nanostructures.
- Fabrication of nanostructures and masks by using of local anodic oxidation (LAO)
- Study of local anodic oxidation (LAO) by AFM.
- Application of AFM in fabrication of masks and grids for nanoelectronics and nanophotonics.
- Interaction of very slow electrons with two-dimensional crystals
The dissertation will be concentrated on problems of interaction of very slow electrons with 2D crystals, in particular with the graphene. The aim will be to elucidate relation between the method of preparation of the graphene and presence of fluctuations in the reflectivity of very slow electrons from the graphene on a substrate as well as from the free-standing graphene. Activities will include preparation of the graphene with various methods and its microscopic diagnostics in an ultrahigh vacuum scanning electron microscope and in a microscope with a standard vacuum. Furthermore, the phenomenon of removal of adsorbed overlayers owing to impact of slow electrons will be examined in detail, together with its influence on transmissivity and reflectivity of the graphene. Besides the graphene also other 2D crystals will be included in the study according to their availability. Publication of results is supposed, preferentially in international journals.
- Ion Beam Assisted Deposition (IBAD), part II.
Ion Beam Assisted Deposition (IBAD) of thin films ZrO2, HfO2, Al2O3, hydroxylapatite.
- Modern methods of design of electron optics systems and aberration coefficients determination
- matrix method for computations in electron optics
- influence of tolerancing and 5th order aberrations
- implementation of the differential algebra method for the computation of aberration coefficients of an arbitrary order
- Nanophotonics - Application of localized of surface plasmons
Application of plasmon polaritons in nanophotonics>
- Fabrication of plasmonic nanostrucutres (e.g. nanoantennas) and a study of their influence on local excitation of electromagnetic. radiation.
- Application of plasmonic nanostructures in local excitation of photoluminescence or enhancement of solar cell efficiency.
- Selective growth of nanostructures
Development of hybrid methods of the selective growth of nanostructures on patterned substrates:
- patterning of sample surfaces by nanolithographic methods (FIB, SEM, SPM),
- selective growth of metallic or semiconductor (e.g. GaN) nanostructures on these surfaces by sputtering under UHV conditions or by deposition from colloidal solutions.
- Study of physical properties of nanostructures
- Building an apparatus for the measurements of local and integral photoluminescence properties of nanostructures
- Study of photoluminescence properties of nanostructures (ordered and disordered semiconductor/dielectric structures)
Oxide materials will be prepared employing pulsed laser deposition (PLD) in vacuum chamber and analyzed in-situ by scanning probe microscopies (STM/AFM), low energy electron diffraction (LEED) and X-ray photoelectron spectroscopy (XPS). The aim is to discover novel materials for catalysis.