Optical Properties of Vanadium Pentoxide Thin Films Prepared by Thermal Evaporation Method

Vanadium Pentoxide (V2O5) thin films were obtained using thermal evaporation technique on a glass substrate. Many films of different thicknesses were prepared. Deposition rate was controlled by using a quartz monitor connected with the system and the rate was about 5 nm per second for all films. The transmittance and reflectance of each film, in the spectral range 300 to 900 nm, were measured from which the optical constants (Refractive index, Absorption coefficient, Extinction coefficient and Energy gap) were determined. The energy gap was calculated for two films (d(1) = 320 nm and d(2) = 700 nm) and found to be 1.87 and 2.1 eV for the direct allowed transitions, respectively. All measured values were consistent with those found in other previous studies. All our films were found to have an amorphous structure as was shown by the XRD patterns of the films.