摘要
The optical transmission spectrum of amorphous Se films prepared by plasma-enhanced chemical vapour deposition was measured over the 500 to 2000 nm spectral region. The absorption coefficient values plotted vs photon energy according to Tauc's law yielded an optical gap, Eg, of 1.94 eV. The temperature dependence of Eg was measured between 13 K and 300 K and was found to be well described within Fan's one-phonon approximation. Photo-induced darkening of the optical gap was studied by illumination at 13 K and 77 K.