Physical properties of multilayer thin films of Ti-V and their hydrides studied by ion beam analysis methods

摘要

Titanium, titanium dioxide and vanadium oxide thin films, as well as V2O5/TiO2 systems were deposited onto Si (111) substrates. For some samples, 1/3 of the surface was covered with palladium using molecular beam epitaxy. Chemical composition, density and layer thickness of the layers were determined by RBS [1]. Samples have been charged with hydrogen 5 times (titanium films) and 3 times (vanadium oxide films) under pressure of 1 bar and at temperature of 300°C. Hydrogen depth profile was determined using Secondary Ion Mass Spectrometry (SIMS) and Nuclear Reaction Analysis (N-15 method). NRA measurements proved a higher hydrogen concentration in samples with partially covered top layers, than in samples without palladium indicating that palladium acts as a catalyst for hydrogen diffusion through the TiO2 layer. RBS measurements showed reduction of V2O5 after each hydrogen charging, and VO2 composition have been obtained after the third process. Further measurements, in particular hydrogen profiling, are in progress.