Kristina Šliužienė

Growth and investigation of p-n structures based on Fe3O4thin films

We report preparation and investigation of p-n heterostructures based on Fe3O4 thin films grown on n-Si(111) substrates as well as indium oxide (IO) and tin doped indium oxide (ITO) layers deposited on lattice-matched monocrystalline ZrO2:Y2O3(100). Thin Fe3O4 films with thickness ranging from 100 to 300 nm were grown in situ at 400 K using dc magnetron sputtering technique. The measurement of microstructure revealed polycrystalline quality of Fe3O4 films on silicon substrate and epitaxial growth on (IO)ITO/YSZ. Investigation of surface composition by X-ray Photoelectron Spectroscopy (XPS) showed that Fe 2p peak consists of three main peaks, namely, metallic iron Fe(0), Fe(II) and Fe(III). Transport measurements of Fe3O4/n-Si heterostructures demonstrated rectifying behaviour in a wide temperature range (T = 78÷300 K) while those prepared by growing Fe3O4 layers on indium oxide (IO) demonstrated nonlinear current-voltage (I-V) dependencies at low temperatures (T<120K).

THE TERAHERTZ EMISSION AND PHOTOELECTRON SPECTROSCOPY STUDY OF CuInS 2 THIN FILMS

CuInS2 thin films were produced by a two-stage process by means of the sulfurisation of magnetron-sputtered metallic precursor layers on molybdenum-covered soda-lime glass substrates. Terahertz pulse generation from the surface of CuInS2 thin films excited by femtosecond laser pulses was studied. Terahertz radiation efficiency is dependent on the stoichiometry of the films obtained. The interface formation between vacuumevaporated CdS and CuInS2 thin films was studied by photoelectron spectroscopy using synchrotron radiation. The valence band offset of 0.7 ± 0.1 eV was determined for the CdS/CuInS2 heterojunction.