The optical absorption coefficient of amorphous 40TeO2-(60-x) V2O5-xMoO3 thin films was determined in a spectral range 190-1100 nm at room temperature. The fundamental optical absorption edge was sharp. The optical gap generally increases as the proportion of MoO3 in the mixed films was increased; also, the width of the tail of the localized states in the band gap was determined for different compositions, which are arising from the lack of long range order and the results were discussed in terms of the usual density-of-state models of amorphous materials.
