Electrochemical Formation and Selenization of Ternary CuZnSn Alloys for Growing CuZnSnSe Photoactive Thin Films

A two-step electrochemical route for the synthesis of Cu 2 ZnSnSe 4 (CZTSe) photoactive thin films is reported in this work. A ternary Cu-Zn-Sn (CZT) alloy was electrochemically deposited onto Indium doped Tin Oxide (ITO) substrates from citrate electrolyte followed by a thin layer of Se on the top. The CZT + Se deposits were annealed under vacuum and characterized by means of field emission scanning electron microscopy (FESEM), energy dispersive spectrometry (EDS), X-ray diffraction (XRD), Raman spectroscopy and UV-VIS spectroscopy respectively. The XRD measurements indicated that when annealed under vacuum at 350 °C, the manufactured CZT+ Se precursors contained the main diffraction peaks of CZTSe in addition to secondary phases such as Cu 6 Sn 5 and Cu 5 Zn 8 binaries. With increasing temperature up to 550 °C, the CZTSe deposits presented stannite structure with a band gap of 1.12 eV and contained traces of Cu 2 SnSe 3 phase.