Electrochemical Formation and Selenization of Ternary CuZnSn Alloys for Growing Cu₂ZnSnSe₄ Photoactive Thin Films

摘要

A two-step electrochemical route for the synthesis of Cu2ZnSnSe4 (CZTSe) photoactive thin films isreported in this work. A ternary Cu-Zn-Sn (CZT) alloy was electrochemically deposited onto Indiumdoped 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 emissionscanning electron microscopy (FESEM), energy dispersive spectrometry (EDS), X-ray diffraction(XRD), Raman spectroscopy and UV-VIS spectroscopy respectively. The XRD measurementsindicated that when annealed under vacuum at 350 C, the manufactured CZT+ Se precursorscontained the main diffraction peaks of CZTSe in addition to secondary phases such as Cu6Sn5 andCu5Zn8 binaries. With increasing temperature up to 550 C, the CZTSe deposits presented stannitestructure with a band gap of 1.12 eV and contained traces of Cu2SnSe3 phase.