Investigation of Optical Properties of Amorphous Gap Films

The optical properties of amorphous Gap (a-Gap) films prepared by plasma enhanced transport deposition method in the system of Ga-PCl₃-H₂ have been studied. The optical energy band gap E^opt_g of a-Gap films is about 1.6 e V which depends on the contents of Cl atoms. The results of exponential absorption edge indicate that there is a high density of band-tail states in the optical energy band gap.