Electrodeposited Cu2O doped with Cl : electrical and optical properties

Abstract

For understanding the electrical and optical properties of electrodeposited Cl-doped Cu2O thin films, we have studied layers with increasing thickness and Cl concentrations of 0.8 and 1.2 at. %. The deposits were characterized by measuring the charge transport, the optical reflectance, and the photoluminescence. No significant decrease of electrical resistivity was observed in doped samples compared to undoped ones. A decrease of about five orders of magnitude was measured and ascribed to the presence of pinholes, as confirmed by scanning electron microscopy analyses. From optical measurements, we concluded that the Cl atoms are incorporated into substitutional sites of Cu2O lattices in agreement with photoluminescence results showing a strong reduction in the peak intensity of VO þ2 defects in comparison to undoped layers. Computational calculation using density functional theory has pointed out high formation energy for single Cl related defects, but low formation energy for Cl-defect complexes, such as ClOþVCu, that strongly compensate the carriers generated by the Cl doping.