Surface Morphology of Cu(Zn, Sn) Metal Precursor for Solar Cell Applications

Cu(Zn, Sn)(CZT) metal precursors were deposited on glass substrates by an RF-magnetron sputtering method for use in CZT-based solar cells. Recently, researches have shown that CZT-based solar cell films prepared with a metal precursor with a rough surface morphology produce a low conversion efficiency. A single layer of tin (Sn) grown on a substrate has a rough surface morphology. In this study, the co-sputtering method was used, wherein Zn, Cu, and Sn layers were deposited on co-sputtered layers of Cu-Sn, Zn-Sn, and Cu-Zn, respectively. From an atomic force microscopy analysis, the root-mean-square surface roughness of the Zn/Cu-Sn layer was found to be 12.3∼14.3 times smaller than that of the other layers precursors, Cu/Zn-Sn, and Sn/Cu-Zn.