Study of electron transport and light-induced effects in a-SiH films

Electron lifetimes and mobility-lifetime products before and after exposure to white, blue or red light have been estimated on the basis of steady-state photocurrent measurements using, delayed-field (DF) and time-of-flight (TOF) techniques. The sample had the structure glass /transparent-conductive-oxide/a-SiC(300 A)/a-SiH(10 microns)/ a-SiC(300 A)/ metal. From transient photocurrent measurements (DF and TOF), it was found that a change occurs in mobility-lifetime products and lifetimes of the electrons. The trapping lifetime of the electrons was reduced by light soaking. This short lifetime is attributed to an increase of deep trapping centers or recombination centers with large cross sections.