Room temperature photoluminescence and spectroscopic ellipsometry of reactive co-sputtered Cu-doped ZnO thin films

In this present work, reactive co-sputtering (DC) has been used to deposit the pure ZnO and Cu-doped ZnO (Cu-ZnO) thin films on a glass substrate. The copper atoms are subsumed into ZnO thin film by co-sputtering(RF) of a pure copper target. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Raman spectroscopy, Photoluminescence spectroscopy (PL), UV-Visible spectroscopy, and ellipsometry were used to examine pure ZnO and Cu-doped ZnO thin films. XRD reveals the wurtzite crystal structure for both pure and Cu-doped ZnO thin films. FESEM images show the dense and uniform surface morphology of all thin films. Energy-dispersive X-ray analysis (EDS) confirms the uniform distribution of copper dopant and variation in doping percentage in the Cu-doped ZnO films. The PL spectra of Cu-doped ZnO film have strong violet emission which shows a variation in zinc vacancy (V-Zn) defect density levels. UV-Vis-NIR spectroscopy has confirmed a slight increase in optical band gap by copper doping. The refractive index, roughness, and film thickness have been calculated using spectroscopic ellipsometry and found to increase with Cu doping concentration.

Automated summary

In this study, pure ZnO and Cu-doped ZnO thin films were deposited on a glass substrate using reactive co-sputtering. The structural, morphological, and optical properties of the thin films were characterized. The results showed that Cu doping modified the crystal structure, surface morphology, and optical properties of ZnO thin films. These findings are important for the research and applications of Cu-doped ZnO thin films.