Preparation of CuIn(S,Se)2 films by PLD of precursor layers and post‐annealing and their application to solar cells

Abstract

Cu‐In‐S precursor films were deposited at various substrate temperatures by pulsed laser deposition (PLD). CuIn(S,Se)2 films were prepared by post‐annealing the Cu‐In‐S precursor films in H2S and Se atmosphere. CuIn(S,Se)2 solar cells with a device structure of Au/ITO/i‐ZnO/CdS/CuIn(S,Se)2/Mo/soda‐lime (SLG) glass were fabricated and characterized. Higher conversion efficiency was obtained for the CuIn(S,Se)2 solar cell with the precursor film deposited at room temperature. The phase and microstructure of the Cu‐In‐S precursor and the annealed CuIn(S,Se)2 films were examined by X‐ray diffraction (XRD) and scanning electron microscopy (SEM). We found that the quality of the CuIn(S,Se)2 films was strongly affected by the deposition temperature of Cu‐In‐S precursor films. We discuss the grain growth and sintering in CuIn(S,Se)2 films on the basis of the results of XRD and SEM. The highest conversion efficiency of 6.38% (Voc = 521 mV, Jsc = 22.6 mA cm−2, FF = 0.541) was obtained for the CuIn(S,Se)2 solar cell with the precursor film deposited at room temperature and post‐annealed at 620 °C. The solar cell was analyzed by secondary ion mass spectroscopy (SIMS) and transmission electron microscopy (TEM).