Time-of-Flight Measurement of Undoped Glow-Discharged a-Si:H

Abstract

Time-of-flight measurement has been carried out on glow-discharged a-Si: H films. It is observed that the electron transport is fairly non-dispersive above room temperature, while holes have a highly-dispersive nature. In its temperature dependence, the electron mobility shows a tendency to saturate at higher temperatures and has an activation energy of 0.2 eV in the low-temperature region. From the saturation characteristic of the relation between the electron-induced charge and the applied field on thin samples, the µ_dτ product is estimated to be about 2.6-6×10^-9cm²/V at room temperature. A model based on a multiphase structure of a-Si: H is proposed to explain, in a consistent manner, the characteristic transport of electrons and holes.