The density of localized states in a-$S_i$ prepared by vacuum evaporation was investigated by the Field Effect Technique. Substrate temperature was 350 ℃ and deposition rates of less than 1.5A/sec were employed during deposition.
The density of localized states at the Fermi level is about $10^{18} cm^{-3}eV^{-1}$ and is larger than that of the sample prepared by glow discharge decomposition of $S_iH_4$.
The density of localized states was found to change with Hydrogenation temperatured and was minimized at T_H=350 ℃.
Fermi level of the a-$S_i$ Hydrogenated at 300 ℃ was 0.59 eV below the mobility edge.
In low temperature region, variable range hopping was observed. The analysis of the results were carried out using various theoretical models.