Copper nitride: a versatile semiconductor with great potential for next-generation photovoltaics

Abstract

Copper nitride (Cu₃N) has gained significant attention recently due to its potential in several scientific and technological applications. This study focuses on using Cu₃N as a solar absorber in photovoltaic technology. Cu₃N thin films were deposited on glass substrates and silicon wafers by radio-frequency magnetron sputtering at different nitrogen flow ratios with total pressures ranging from 1.0 to 5.0 Pa. The thin films' structural, morphology and chemical properties were determined by XRD, Raman, AFM and SEM/EDS techniques. The results revealed that the Cu₃N films exhibited a polycrystalline structure, with the preferred orientation varying from (100) to (111) depending on the working pressure employed. Raman spectroscopy confirmed the presence of Cu-N bonds through characteristic peaks observed in the 618-627 cm^-1 range. While SEM and AFM images confirmed the presence of uniform and smooth surface morphologies. The optical properties of the films were investigated using UV-VIS-NIR spectroscopy and photothermal de-flection spectroscopy (PDS). The obtained band gap, refractive index, and Urbach energy values demonstrated promising optical properties for Cu₃N, indicating their potential as solar absorbers in photovoltaic technology. This study highlights the favorable properties of Cu₃N films deposited by the RF sputtering method, paving the way for their implementation in thin-film photovoltaic technologies. These findings contribute to the progress and optimisation of Cu₃N-based materials for efficient solar energy conversion.