OPTICAL-ABSORPTION AND STRUCTURAL CHARACTERIZATION OF REACTIVELY SPUTTERED TELLURIUM SUBOXIDE THIN-FILMS

Tellurium suboxide (TeOx) thin films were deposited on non-intentionally heated fused quartz substrates by RF reactive sputtering, with x = 1.3, as calculated from Rutherford backscattering spectroscopy measurements. Optical studies were performed in air at room temperature for both as-deposited and thermally annealed (250-degrees-C for 5 min in Ar atmosphere) films. The refractive index n and the extinction coefficient k were evaluated through transmissivity and reflectivity measurements at room temperature in the range of wavelengths between 200 and 1500 nm. The optical absorption spectrum as a function of the incident photon energy was also determined in order to evaluate the optical gap. Finally electron microscopy analysis has revealed that the film structure attains a shorter range order after the annealing.