Comparative study of Cu(In,Ga)Se2/CdS and Cu(In,Ga)Se2/In2S3 systems by surface photovoltage techniques

Abstract Cu(In,Ga)Se 2 absorbers were investigated by surface photovoltage (SPV) in the Kelvin probe and fixed capacitor arrangements before and after deposition of CdS or In 2 S 3 buffer layers as well as before and after deposition of ZnO window layers. Effects such as passivation of surface states, partial electron transfer from ZnO into In 2 S 3 , decrease of the ideality factor after deposition of ZnO and slow electron transfer through In 2 S 3 were demonstrated. The results show that SPV measurements open opportunities for dedicated studies of charge separation at hetero-junctions between ordered and disordered semiconductors.