Tailoring the properties of spray deposited V2O5 thin films using swift heavy ion beam irradiation

Abstract

Swift heavy ion (SHI) beam irradiation can generate desirable defects in materials by transferring sufficient energy to the lattice that favours huge possibilities in tailoring of materials. The effect of Ag15+ ion irradiation with energy 200 MeV on spray deposited V2O5 thin films of thickness 253 nm is studied at various ion doses from 5 × 1011 to 1 × 1013 ions/cm2. The XRD results of pristine film confirmed orthorhombic structure of V2O5 and its average crystallite size was found to be 20 nm. The peak at 394 cm−1 in Raman spectra confirmed O–V–O bonding of V2O5, whereas 917 cm−1 arise because of distortion in stoichiometry by a loss of oxygen atoms. Raman peaks vanished completely above the ion fluence of 5 × 1012 ions/cm2. Optical studies by UV–Vis spectroscopy shows decrement in transmittance with an increase in ion fluence up to 5 × 1012 ions/cm2. The red shift is observed both in the direct and indirect band gaps until 5 × 1012 ions/cm2. The surface topography of the pristine film revealed sheath like structure with randomly distributed spherical nano-particles. The roughness of film decreased and the density of spherical nanoparticles increased upon irradiation. Irradiation improved the conductivity significantly for fluence 5 × 1011 ions/cm2 due to band gap reduction and grain growth.