Changes in electric and optical properties of intrinsic microcrystalline silicon upon variation of the structural composition

Device-grade microcrystalline silicon prepared by plasma enhanced chemical vapor deposition is investigated with respect to its structural, electronic and optical properties in order to identify material parameters with relevance to the solar cell efficiency. All sample series show a similar increase of dark conductivity with increasing crystalline volume fraction, suggesting a close relationship between electrical transport and the structural details of the material. Conditions yielding the highest solar cell performance, i.e. close to the transition to amorphous growth, are characterized by the lowest dark conductivity values together with the maximum photosensitivity in the whole crystalline range.