Optical and structural properties of W03 as a function of the annealing temperature

Abstract

This work presents a study of effect of annealing temperatme on optical and structural properties of W03 that has been deposited by hot-filament metal oxide deposition (HFMOD). X-ray diffraction shows that the as-deposited W03 films present mainly monoclinic crystalline phase. The Raman spectrum shows four intense peaks that are typical Raman peaks of crystalline W03 (m-phase) that corresponds to the stretching vibrations of the bridging oxygen that enhance and increase their intensity with the annealing temperature. Band gap can be varied fi•om 2.92 to 3.15 eV by annealing W03 from 0 to 500 °C. The photoluminescence response of the as­ deposited film presents two radiative transitions centered at 2.04 and 2.65 eV that are associated to oxygen vacanc1es.