Structural and optical properties of reactive-sputtered films of V_2O_5 : Measurement of optical bandgap and roughness correction

Abstract

Films of vanadium oxide were prepared by reactive DC magnetron sputtering. Crystalline films of α-V_2O_5 could be obtained at 500℃ for an hour in oxygen atmosphere. Further annealing made rod-like crystallites to grow, and optical spectra of transmittance and reflectance changed with annealing, but the change after the crystallization could be explained by the increase in the surface roughness and the corrected absorption coefficients yielded a value of 2.25 eV for the bandgap energy.