Tuning the opto-electrical properties of AgInS2 films prepared by two- step process

Optical and electrical properties of silver indium sulfide (AgInS2) thin films prepared by two-step process is discussed by varying the deposition time (Td) of silver from 12 to 18 min. Formation of tetragonal AgInS2 crystal structure with preferential orientation along (112) plane is observed from X-ray diffraction studies. Raman analysis confirms the existence of both chalcopyrite structure (274 cm−1) and CuAu ordered structure (305 cm−1). With the increase in deposition time, grain size of AgInS2 films is found to increase from 0.6 to 0.9 µm. All the films exhibited p type conductivity with resistivity ranging in the order of 103 to 104 Ω-cm. Depth profile analysis is carried out to determine the valence states of AgInS2 compound throughout the sample. Films deposited at Td = 16 min showed optimum properties and hence the photovoltaic performance of optimized sample is studied.