This paper deals with the time of flight measurements of the electron drift mobility in hy-drigenated intrinsic amorphous silicon prepared by glow discharge decomposition of silane. The electron-hole pairs are generated on the surface of GD a-Si:H films by a 5-6ns flash of light from a dye laser. The sample is reverse biased so that the photogenerated carriers are swept across the film and then the transient photocurrent is discussed.It is found that electron drift mobilities in these a-Si films prepared under various glow discharge conditions fall in the 0.3-1.2cm2/V.s range.There is an electron-trapped e-ffect at the local states in these a-Si films

therefore all release time constants of trapped electrons are larger than 1 μs.