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).