Abstract. Published electron and hole drift-mobility measurements in hydrogenated amorphous silicon (a-Si:H), amorphous silicon alloys (a-SiGe:H and a-SiC:H), and microcrystalline silicon (μc-Si:H) are analysed in terms of the exponential bandtail trapping model. A three-parameter model was employed using an exponential bandtail width ΔE, the band mobility μ₀, and the attempt-to-escape frequency ν. Low-temperature measurements indicate a value around μ₀ = 1 cm² V⁻¹ s⁻¹ for both the conduction and valence bands over the entire range of materials. High temperature-measurements for electrons in a-Si:H suggest a larger value of 7 cm² V⁻¹ s⁻¹. These properties and those of the frequency ν are discussed as possible attributes of a mobility edge.

Print publication: Issue 44 (10 November 2004)
Received 26 August 2004, in final form 27 August 2004
Published 22 October 2004