Study on the effect of annealing and swift heavy ions irradiation on vanadium oxide thin films

Abstract

Vanadium oxides are of novel interest for the last few decades due to their interesting electrical, structural and optical properties. The characteristic features of vanadium oxide films can be altered by doping, annealing, stress and ion beam irradiation. Swift heavy ions irradiation is a versatile tool to create high pressure, temperature and defect density in controlled fashion in the material. Therefore, it becomes an interesting area to explore the changes in the properties of vanadium oxide films by swift heavy ions (SHIs) irradiation. In this study, vanadium oxide thin films have been deposited on the silicon (Si) substrate by using different techniques such as radio frequency (RF) sputtering, pulsed laser deposition, reactive RF sputtering and e-beam evaporation methods. Vanadium pentoxide (V2O5) powder is used as a source C for twoand#61616;material. A pellet is formed from the V2O5 powder and it is sintered at 400 hours in the normal conditions. Films, deposited by different techniques, are annealed C for one hour. Thin films (annealed andand#61616;in the neutral environment (argon) at 500 as-deposited) are irradiated with SHIs at different fluences (1×1011, 5×1011 and 5×1012 ions/cm2 ) at room temperature. To study the modifications in the properties of vanadium oxide thin films due to annealing and irradiation, various characterization techniques have been employed. Structural characterization is performed by grazing incidence X-ray diffraction (GIXRD). Vibrational properties of the thin films have been analyzed by Raman and Fourier transform infrared spectroscopy (FTIR). Optical property was studied by UV-vis-NIR spectrophotometer. Characterization results revealed that a stable phase of vanadium oxide is obtained by post annealing. Further, oxygen vanadium (O/V) concentration in the films changes with SHIs irradiation. This change in concentration reduces the oxidation state of vanadium species in vanadium oxygen system. The reduction of oxidation state transforms the phase of vanadium oxide thin films. SHIs irradiat