Effect of Ion Irradiation on Vanadium Oxide Thin Films Deposited by Reactive RF Sputtering Technique

Abstract

Vanadium has many oxides (VO2, V2O3, V2O4, V6O13 and V2O5) due to high oxidation state. Properties of the vanadium oxide thin films can be changed by pressure, doping and strain. Ion irradiation can transform the phase, mix the two solid materials, form epitaxial crystallization and create nanostructure etc. in the materials. Purpose of our study was to observe the effect of swift heavy ions (SHIs) irradiation on vanadium oxide thin films. Thin films of vanadium oxide were deposited on the Si substrate by reactive RF sputtering technique. As-deposited thin films were irradiated by swift heavy ions (100 MeV Ag ions) at different fluences at room temperature. The effect of ions irradiation was studied by using grazing incidence X-ray diffraction (GIXRD), Fourier transform infrared spectroscopy (FTIR) and UV-vis-NIR spectrophotometer characterization techniques. GIXRD pattern revealed that swift heavy ions can induce the phase transformation (V6O13 to V2O3) in the films. FTIR characterization showed that δ(V=O) stretching mode at 1020 cm-1 shifted to the lower wave number side. Optical properties showed blue shift in the absorption spectra at the higher fluences. These shifting are due to the lowering of vanadium’s oxidation state in the thin films. This change in oxidation state of vanadium transforms the phase of the films. Irradiation with SHIs can transform the phase along with enhancement in the crystallinity of the vanadium oxide films.