Formation of CuIn(S,Se) 2 thin film by thermal diffusion of sulfur and selenium vapours into Cu–In alloy within a closed graphite container

• Published in: Solar energy materials and solar cells 1999-01, Vol.58 (3), p.287-297
• Main Authors: Adurodija, F.O, Song, J, O. Asia, I, Yoon, K.H
• Format: Article
• Language: English
• Subjects: Applied sciences; Copper indium selenide; Energy; Exact sciences and technology; Natural energy; Photovoltaic conversion; Solar cells; Solar cells. Photoelectrochemical cells; Solar energy; Thin film
• ISSN: 0927-0248; 1879-3398
• DOI: 10.1016/S0927-0248(99)00011-2

The formation of CuIn(S,Se) 2 thin films by thermal diffusion of sulfur (S) and selenium (Se) vapours into co-sputtered Cu–In alloy within a closed-space graphite container is reported. All films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), Four-point-probe and hot-probe measurements. Cu–In alloy films with composition varying from Cu-rich to In-rich were deposited. The synthesized In-rich films yielded CuIn 5(S,Se) 8 spinel compound which gradually transformed into a single phase CuIn(S,Se) 2 as the film composition approached the Cu-rich region. The morphology of the CuIn 5(S,Se) 8 was found to differ from the stoichiometric and Cu-rich CuIn(S,Se) 2 as observed from SEM. EDX composition analysis of the films showed a Cu/In ratio varying from 0.36 to 1.54 and a (S+Se)/(Cu+In) varying from 0.97 to 1.32. The amount of S incorporated in the films was found to differ with changes in the composition. The resistivity of the films ranged between 10 −1 and 10 7 Ω cm and it strongly followed the change in the alloy film composition.