Tailoring the Optical Properties of CZO Thin Films Grown by Pulsed Spray‐Pyrolysis

The present work analyzes the effect of Cu alloying in ZnO on the optical and structural properties of ZnO:Cu (CZO) thin films deposited by the pulsed spray‐pyrolysis technique from molecular solutions. The study used XRD, SEM, EDX, Raman spectroscopy, and optical spectroscopy. The films are single‐phase, with a hexagonal wurtzite structure, and do not contain secondary phases, as confirmed by XRD and Raman spectroscopy. EDX analysis confirmed the effective incorporation of Cu atoms into the ZnO crystal lattice. The bandgap width changes insignificantly upon alloying, remaining within the range of 3.32–3.33 eV. The analysis of the Urbach energy E U revealed an overall tendency to increase with increasing Cu content. With increasing Cu concentration, the film thickness decreases, accompanied by a reduction in the refractive index n in the long‐wavelength region from 1.58 to 1.51 at λ = 598 nm. The extinction coefficient k increases from 0.0062 to 0.015 with increasing Cu content, and the parameters n , k , ɛ 1 , and ɛ 2 demonstrate a consistent variation with increasing alloying level. The results demonstrate the possibility of controlling the structural and optical properties of ZnO films through precisely controlled copper alloying, opening the way for their potential application in optoelectronic devices and photovoltaic systems, thereby contributing to the development of clean energy technologies and improved energy efficiency.