Relation between the dark and photoelectronic properties of microcrystalline silicon

The dark conductivity, photoconductivity, and diffusion length have been determined in a comprehensive study on microcrystalline silicon samples, prepared under different deposition conditions: variation of substrate temperature, pressure, power, and silane to hydrogen ratio. The results show that the dark and majority carrier properties are correlated, which can be attributed to a Fermi-level related recombination rate and majority-carrier lifetime. In contrast, the observed distinct variation of the minority-carrier properties within a deposition series allows a more direct access to sample quality, as it cannot be directly linked with a Fermi level dependent lifetime. In contrast to the suggestion in the literature, the ratio of the mobility-lifetime products of both carrier types is shown not to be directly related to the Fermi level position.