Low-cost deposition of cupric oxide thin films for optoelectronic applications

Abstract

Copper oxide is a compound that has been considered significant owing to its many advantages such as easy availability of copper in huge quantity, its non-toxic nature and the good electrical and optical properties. It is p-type with bandgap range of 1.21–1.51 eV and has potential of absorption of solar spectrum. In this work, sol–gel chemistry is explored to deposit CuO using cupric chloride dihydrate (CuCl2 · 2H2O) with 5, 10 and 15% concentration of EDTA (capping agent) using low-cost dip-coating and annealed at 400 °C. The bandgap of the CuO films was found to be in the range of 1.3–1.8 eV, which is comparable with the reported values and also suggests quantum shift in these nanostructures. These investigations suggest suitability of these layers as absorber for photovoltaic applications. SEM investigation suggests the uniform growth of layers by dip-coating techniques. Capping also appears to control the grain growth as observed by electron microscopy. Sol–gel dip-coating technique is presented in this study for deposition of flat layers.