Photoelectrochemical study of AgInS₂ thin films prepared using sulfurization of evaporated metal precursors

The AgInS₂ polycrystalline films were grown on glass substrates by using sulfurization of evaporated metal precursors. New procedures for the growth of AgInS₂ films are presented. The influences of [Ag]/[In] molar ratio in the precursor films on structural, optical, electrical performances of films have been investigated. The X-ray diffraction patterns of the samples demonstrate the presence of polycrystalline structures of AgInS ₂ phase in these films. The band gaps and carrier densities of these samples determined from transmittance spectra and electrochemical analysis are in the range of 1.92∼1.94 eV, and 3.2×10²⁰∼4. 0×10²⁰ cm^-3, respectively. The flat band potentials of these samples are located between -0.83 and -1.10 V versus normal hydrogen electrode with the Mott-Schottky measurements. The maximum photocurrent density of samples prepared in this study with external potential kept at +1.0 V (vs. Ag/AgCl electrode) was found to be 4.4 mA/cm² under the illumination with white light intensity kept at 100 mW/cm².