Optical absorption and electrical conductivity measurements of microcrystalline silicon layers grown by SiF4/H2 plasma on glass substrates

Abstract Microcrystalline silicon (μc-Si) films, having different crystalline fractions ( f c ) and thicknesses, were deposited on glass by plasma enhanced chemical vapor deposition (PECVD) starting from a SIF 4 /H 2 /He gas mixture. The absorption coefficient (α) in the energy range 0.8–2.0 eV was evaluated from the standard constant photocurrent method (S-CPM) and dark conductivity measurements have been performed. The S-CPM data elaboration was carried out according to the Favre approach, in order to take account for the bulk scattering. The true α(α true ) vs. energy trend was interpreted to evidence defect density and the crystalline-amorphous fraction of the samples. However, no thickness effect on the α true coefficient was observed, whereas the change in crystalline fraction resulted in different scattering effects.