Temperature dependence of the photoconductivity and the near absence of light-induced defects in a-Si{sub x}Ge{sub 1-x}:H

The photoconductivities {sigma}{sub p} of glow discharge deposited a-Ge:H and amorphous Si-Ge alloys prepared in different laboratories were measured between 4.2K and 300K and compared with {sigma}{sub p}(T) of intrinsic and compensated a-Si:H films. The alloys as well as a-Ge:H do not exhibit thermal quenching of {sigma}{sub p}(T) at elevated temperatures which suggests that the valence and conduction band tails have similar widths. Remarkable is the near absence of light-induced metastable defects in the alloys as in a-Ge:H even after prolonged exposures at low temperatures.