Spectroscopic and electrical analysis of spray deposited copper oxide thin films

Copper Oxide (CuO) in thin film form is an excellent candidate for absorber layer in solar cells due to their adequate band gap, minimal cost, and large abundance. In this work, CuO thin films were grown on glass substrates by spray pyrolysis technique. The impact of substrate temperature and precursor concentration on the structural, morphological, optical, and electrical properties of the films were thoroughly investigated. The formation of polycrystalline tenorite phase CuO was confirmed by X-ray diffractogram. FESEM showed morphological homogeneity of the films and EDAX validated the presence of O and Cu in the samples. Spectrophotometric experiments revealed that CuO films exhibit a considerable absorption in the visible range, which gradually decreased after 800 nm. The film's estimated band gap was near to the solar absorption band gap, indicating that they can be employed as absorber layers in solar cells. The formation of tenorite phase CuO was further confirmed by Raman analysis. The optical emission properties of the CuO films were studied by photoluminescence spectroscopy. X-ray Photoelectron Spectroscopy revealed the presence of Cu₂O in minor fraction along with CuO. Hall measurements were done to study the electrical properties like resistivity, mobility, and carrier density.