Comparative study of structural and morphological properties of CuIn3S5 and CuIn7S11 materials

CuIn3S5 and CuIn7S11 powders were prepared by solid-state reaction method using high-purity elemental copper, indium and sulphur. The films prepared from CuIn3S5 and CuIn7S11 powders were grown by thermal evaporation under vacuum (10−6 Torr) on glass substrates at different substrate temperature Ts varying from room temperature to 200 °C. The powders and thin films were characterized for their structural properties by using X-ray diffraction (XRD) and energy dispersive X-ray (EDX). Both powders were polycrystalline with chalcopyrite and spinel structure, respectively. From the XRD data, we calculated the lattice parameters of the structure for the compounds. For CuIn3S5 powder, we also calculated the cation-anion bond lengths. The effect of substrate temperature Ts on the structural properties of the films, such as crystal phase, preferred orientation and crystallinity was investigated. Indeed, X-ray diffraction analysis revealed that the films deposited at a room temperature (30 °C) are amorphous in nature while those deposited on heated were polycrystalline with a preferred orientation along (1 1 2) of the chalcopyrite phase and (3 1 1) of the spinel phase for CuIn3S5 and CuIn7S11 films prepared from powders, respectively. The morphology of the films was determined by atomic force microscopy AFM. The surface roughness and the grain size of the films increase on increasing the substrate temperature.