Growth and characterization of single phase AgInS2 crystals for energy conversion application through β-In2S3 by thermal evaporation

Abstract Silver indium sulfide thin films have been successfully synthesized out from β-In 2 S 3 buffer layers using appropriate heat treatments of evaporated β-In 2 S 3 /Ag. X-ray analysis show that the β-In 2 S 3 /Ag crystalline films with 60 nm thickness of Ag, which were annealed under sulfur atmosphere at 400 °C, were mainly formed by the ternary AgInS 2 . Raman spectra confirmed that the observed peaks were characteristics to AgInS 2 chalcopyrite of thin film structure. The optical band gap of AgInS 2 , which was evaluated as nearly 1.80 eV, was confirmed by the electrical study which yielded a value in the order of 1.78 eV. The electrical conductivity, conduction mechanism, dielectric properties and relaxation model of this thin film were studied using impedance spectroscopy technique in the frequency range 5 Hz–13 MHz under various temperatures (370–440 °C). Besides, complex impedance, AC conductivity and complex electric modulus have been investigated on the basis of frequency and temperature dependence.