Abstract
We report on the structural, optical and electrical properties of RF sputtered Niobium pentoxide (Nb2O5) thin films. The structural studies have been carried out using XRD, and AFM techniques. Optical constants such as optical band gap energy, absorption coefficient, refractive index, complex dielectric constant and optical conductivity have been estimated for as-deposited and annealed Nb2O5 thin films. The estimated direct optical band gap energy values were found to be E-g(d) = 3.62 eV for the as deposited which = decreases to E-g(d) = 3.07 eV for the annealed films at 973 K. The dispersion curves of the refractive index of Nb2O5 thin films in the optical transparency region are explained by using single oscillator and Drude models. The correlations between optical parameters and the annealing temperature of the Nb2O5 thin films are discussed. The DC activation energy has been estimated by using two probe technique. Mott's variable range hopping conduction process (VRH) and small-polaron hopping have been used to understand DC electrical conductivity.