Effect of substrate temperature on the properties of Nb2O5:MoO3 (90:10) thin films prepared by rf magnetron sputtering technique

Abstract

In this work, the effect of substrate temperature on the structural, optical, vibrational and electrochromic properties of radio frequency (rf) magnetron sputter deposited mixed Nb2O5:MoO3 (90:10) thin films have been studied. X-ray diffraction analysis revealed that all the deposited films belong to amorphous nature. The x-ray photoelectron spectroscopic study confirms the compositional purity and the presence of five-valent niobium (Nb5+) and six-valent molybdenum (Mo6+) in the deposited film. The average optical transmittance of the films varied between 88 and 92%. The refractive index and extinction coefficient of films are found to decrease with increasing substrate temperature. Photoluminescence spectra exhibit three characteristic emission peaks and confirm the better optical quality of the deposited film. The longitudinal and transverse optic modes of Nb–O stretching vibrations were observed from the micro-Raman study. The cyclic voltammograms of Li+ and H+ ions clearly show all the films are having better reversibility and reproducibility in their electrochemical analysis. The maximum coloration efficiency of 51.94 cm2/C was obtained for the mixed Nb2O5:MoO3 (90:10) film.