Photo-generated carriers decay behavior of nano-crystalline β-SiC thin film irradiated by pulse laser

Abstract

The photo-generated carriers decay behavior of microcrystalline and nanocrystalline β-SiC films grown by helicon wave plasma-enhanced chemical vapor deposition process is measured by microwave absorption technique. The decay of the photo-generated carriers concentration includes a fast and a slow component. The measured transient decay curve of microwave absorption signal can be fitted fairly with a sum of two exponential decay functions, which indicates that the decay process is governed by two different traps. The results show that the transient decay behavior of the films is closely related with their micro-structrue. The nonradiative recombination which gives priority to the photo-generated carriers decay process involves multiple energy transition processes. A relationship between the time constant and the energy location has been obtained.