“In situ” measurements of the transient photoconductivity in a-Si:H

During glow discharge deposition of a-Si:H the transient photoconductivity is measured with the time-resolved microwave conductivity method. The change of the signal with deposition time is discussed. Evidence is given that the defect density is larger in the surface layer. Analysis of the maximum signal height as a function of the film thickness gives the absorption coefficient at the excitation wavelength. Influence of the deposition temperature on the properties of the film is studied. It is found that lowering the substrate temperature yields films with a larger charge carrier decay rate.