Charge-selective disordered hetero-junctions were formed in evaporated In2S3 layers by diffusing at 200 °C CuI from a CuSCN source. The thicknesses of In2S3 layers and diffusion times were varied between 5 and 80 nm and between 2 and 19 min, respectively. In some cases CuSCN layers were etched back with pyridine. Spectral and time-dependent surface photovoltage measurements were carried out in the capacitor arrangement. It was observed that a competing process of charge separation and relaxation was initiated together with the formation of the charge-selective In2S3/In2S3:Cu hetero-junction.
Modulated SPV amplitude for different annealing times and thicknesses of the evaporated In2S3 layers.