The energy distribution of localised states, and the mobilities of free carriers in a-Si:H, from time of flight and other measurements

Abstract

Electron and hole time-of-flight measurements in glow-discharge a-Si: H have been made over a wide range of temperatures and electric field. Recently-developed techniques are used to identify the energy distributions of states within the conduction and valence band tails. Free carrier mobilities are also estimated, and whilst the value for electrons is closed to that normally accepted, the figure for holes is about 10 cm 2V −1sec −1, which is an order of magnitude larger than the value often presently assumed.