Depth profiles of mobility lifetime products and capture cross-sections in a-Si:H

Abstract

Time of flight (TOF) with a varying wavelength of the exciting laser has been used to investigate the profile of the μτ product (drift mobility x deep trapping lifetime) in a-Si:H. The authors show that depletion regions, surface states and inhomogeneities may influence the measurement. Further, they discuss the problem of charge collection when both types of carriers (electrons and holes) are involved. Application of this method on a-Si:H Schottky and PIN diodes puts forward the effect of the depletion region on the measured μτ and allows one to give an estimate of the ratio of D + to D 0 capture cross-sections for electrons.