Research
Methods
The development of world-unique (customized) semiconductor characterization methods is one of the main research areas of the Department of SME. We are particularly interested in the development of modulation spectroscopy (photoreflectance, contactless electroreflectance, piezoreflectance, and thermoreflectance) and more recently photoacoustic spectroscopy, time resolved microwave photoconductivity and others.
We are also particularly interested in research on semiconductor materials and heterostructures under hydrostatic pressure and various axial stresses, and we develop appropriate tools for this purpose.
Van der Waals crystals
This research topic includes dichalcogenides (MoS2, MoSe2, MoTe2, WS2, WSe2, ReS2, ReSe2, …), monochalcogenides (GeS, GeSe, SnS, SnSe, …), trichalcogenides (MnPS3, FePS3, CoPS3, NiPS3, …) and many other layered crystals.
Our research focuses on the electronic band structure, examined with optical methods and supported by DFT calculations, as well as on deep defects studied by DLTS and carrier dynamics investigated using TRPL and TRMC. These materials are also considered for applications in semiconductor devices such as photodetectors and gas detectors.
Perovskites
This research topic covers hybrid organic–inorganic perovskites (HOIPs), i.e., 3D (and 2D) crystals with the structural formula ABX3 (ABX4), where A and B are organic and inorganic ions, respectively, and X = Cl−, Br−, or I−. Since these crystals are very soft compared to other semiconductors, our research focuses on optical studies under hydrostatic pressure, including observations of self-trapping excitons and pressure- and temperature-induced phase transitions. Additionally, we are interested in the use of these materials in solar cells and light emitters.
Regular epitaxial semiconductors and heterostructures
This research topic covers group III-V, II-V and group IV semiconductors, including highly mismatched semiconductor alloys grown by epitaxial methods such as MBE or MOVPE. We are particularly interested in studying the electric field distribution in semiconductor heterostructures and the Fermi level position on the semiconductor surface using contactless electroreflectance spectroscopy method. In addition, for this family of materials, we offer a range of measurement services aimed at determining the suitability of given materials and heterostructures in semiconductor devices such as solar cells, photodetectors, light emitters or transistors. Currently, most semiconductor devices are manufactured based on these materials, and we have over twenty years of experience in using standard and advanced optical and electrical methods to characterize these types of semiconductor materials and heterostructures.
Hybrid semiconductor heterostructures
Within this research topic, we are interested in physical phenomena (charge transfer, formation of Schottky barrier or ohmic contact) at heterojunctions of hybrid heterostructures consisting of van der Waals crystals, perovskites and III-V materials, especially GaN and AlGaN. We are also interested in the liquid/semiconductor system in the context of photochemical processes, i.e., water splitting, CO2 reduction and other processes. Contactless electroreflectance and photoreflectance spectroscopy provide an unique opportunity to study the position of the Fermi level at heterojunctions in such heterostructures.
Contact
Prof. Robert Kudrawiec
E-mail: robert.kudrawiec@pwr.edu.pl
Tel. +48 713 204 280
Postal Address
Department of Semiconductor Materials Engineering
Wrocław University of Science and Technology
Wybrzeże Wyspiańskiego 27
50-370 Wrocław
Poland