Temperature dependent photoconductivty and the exponent in the intensity-current relation of a-SiGe:H below room temperature have been investigated. Samples were prepared by glow discharge deposition of pre-mixed gases of silane and germane. As germanium composition ratio is increased, photo coductivty is decreased and the exponent is increased in all temperature ranges. Lowering temperature caused transport paths to change, indicating that there exist three types. The photocurrent is attributed to the hopping transport in lower temperature down to about 50K. Long exposure of lightly alloyed samples to light caused the annealable increase in photocoductivty in low temperature range. This suggests light soaking creates certain hole traps in valence band tails, which have small capture cross sections for the electron.
