Nano-granular indium sulfide layers for thin film solar cells

Abstract

Nano-granular indium sulfide films were prepared by thermal evaporation onto quartz and glass substrates kept at TS = 220–240 °C during the deposition process. High transmittance of the nano-granular indium sulfide films in the visible region has been observed. Correlations between optical properties and morphology of film samples with various thickness have been investigated. Modification of the form and shortwavelength shift of the band edge occur simultaneously upon decreasing of the film thickness from 800 nm up to 30 nm, and the involved mechanisms have been explained. The results indicate that the former effects are assigned to multicomponent composition of the investigated films and that the obtained nanogranular thin films might be proposed as low-cost buffer materials for high-efficient thin-film solar cells with chalcopyrite absorber layers.