Effects of synthesis temperature on CuIn(S,Se)2 thin films prepared by one-step evaporation of Cu–In precursors

Abstract

CuIn(S,Se)2 thin films were grown on soda-lime glass substrates by one-step evaporation Cu–In precursors processes. Effects of synthesis temperature on the structural and optical properties of CuIn(S,Se)2 absorption layers were studied. The changes of surface morphology among different samples were observed by field-emission scanning electron microscopy. From X-ray diffraction images and Raman spectra, the CuIn(S,Se)2 films had good crystallinity quality when the synthesis temperature was 550 °C. The FWHM of (112) peaks decreased from 0.537° to 0.180°, and secondary phase Cux(S,Se) disappeared when the synthesis temperature increased from 300 to 550 °C. The Raman spectra of the films also showed the CuIn(S,Se)2 A1 mode peaks existed chalcopyrite, and the blue shift of the CuIn(S,Se)2 A1 mode peaks from 289 to 284 cm−1. The optical properties of the films were showed by transmission spectra, and the energy band gap of the CuIn(S,Se)2 thin films fabricated at 550 °C is 1.34 eV.