Effect of conductive substrate (working electrode) on the morphology of electrodeposited Cu₂O

Abstract

Cu2O thin films were electrodeposited from a Cu(II) acetate solution containing 0.02 M Copper(II) acetate (Cu(OAc)2) and 0.1 M sodium acetate (NaOAc) at pH 5.6, using three different working conductive electrodes with approximately the same square resistance -indium doped tin oxide glass (ITO/Glass), fluorine-doped tin oxide glass (FTO/Glass), and indium doped tin oxide polyethylene terephthalate (ITO/PET)—under identical conditions using a common growth condition. The Cu2O thin films were characterized by means of scanning electron microscopy, x-ray diffraction (XRD), current density versus growth time for Cu2O films, and electrochemical impedance spectroscopy. The results showed that the choice of substrate materials has a crucial role in controlling Cu2O growth. The charge transfer resistance (Rct) of FTO/Glass-Cu2O exhibits the lowest value; this means that FTO/Glass-Cu2O possess the highest electron transfer efficiency. All Cu2O films showed n-type semiconductor characteristic with charge carrier densities varying between 1.4 × 1018–1.2 × 1019 cm−3.