Electron Mobility Studies in Surface Space-Charge Layers in Vapor-Deposited CdS Films

Abstract

Hall and field-effect surface mobility has been measured in polycrystalline films of CdS of thickness 1000–4000 Å. At low surface potential, the mobility increases with surface potential. The Hall mobility was observed to increase exponentially with temperature from −80° to 120°C. These effects can be explained using a polycrystalline film model. The effects of diffuse surface scattering were not observed at low surface potential due to the small mean free path of electrons. However, when the channel thickness was comparable to the electron mean free path a decrease in mobility was observed.