Structural, electrical, and optical properties of the vacuum evaporated microcrystalline silicon films have been investigated. The films show a preferential growth of the (220) face at low temperatures and the (111) face can be changed into (110) or (200) growth according to the deposition rate. The volume fraction of the crystallites and the size of a crystallite are increased by raising the substrate temperature.
As the volume fraction of crystallites increases, the conductivity activation energy of μc-Si is decreased and optical gap is increased. The increase of optical gap with crystallite volume fraction is due to the second indirect transition $Γ'_{25}'→L_1$ of single crystalline Si.
