Ca-Doped Copper (I) Oxide Deposited via the Spray Coating Technique for Heterojunction Solar Cell Application

Abstract

In this report, the morphological, optical, electrical, and photovoltaic properties of copper oxide and calcium-doped copper oxide thin films produced via the spray coating method were studied. The thermal post treatment at 300 °C in an inert atmosphere allowed us to obtain a single phase of Cu2O with 21 Ωcm of resistivity (ρ). In this study, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, and 10 wt% Ca admixtures with copper oxide were investigated. The determined optimal calcium dopant concentration was 4 wt%. XRD analysis was used to reveal the chemical composition of the produced layers. It was found that a calcium dopant does not change the layer composition but improves its electrical parameters. Based on UV-Vis spectra, the band gap energy and Urbach energy were calculated. The morphology of produced thin films was described as smooth and nanocrystalline, corresponding to a grain size calculated based on the Scherrer equation. Finally, it was shown that the developed protocol of low-resistivity copper oxide deposition via the spray coating technique can be successfully implemented in heterojunction solar cell production. The I–V parameters of Ag/n-type CzSi/REF:CuOx and 4Ca:CuOx/Carbon were collected, and the achieved efficiency was 2.38%.