Thin tantalum pentoxide films have been grown on Si(100) and quartz substrates by photo-induced chemical vapour deposition (CVD) using a 172 nm xenon excimer lamp. The effects of gas pressure and substrate temperature on the properties of the film formed have been studied using ellipsometry, Fourier transform infrared spectrometry: and ultraviolet spectrophotometry. An optical transmittance of around 90% in the visible region of the spectrum was obtained at different pressures. Low temperature (400 degrees C) annealing under vacuum ultraviolet (VUV) irradiation is shown to remove any suboxides present in the as-deposited films, physical and optical characterization both reveal good film qualities. rendering this new technique promising for low temperature microelectronic and optoelectronic material processing.