The role of process temperature on structural, optical, vibrational and electronic environments of thermal chemical vapor-deposited copper-doped zinc oxide nanostructured thin films

Copper incorporated zinc oxide (Cu-ZnO) nanostructure thin films were deposited by using a high-temperature chemical vapor deposition technique at 650-800 degrees C with Cu and Zn powder in O(2)and N(2)gas atmosphere. The Cu-ZnO thin films were characterized by AFM, XRD, FTIR, Raman spectroscopy, UV-Vis spectroscopy, and XPS to investigate the structural, vibrational, optical, and electronic environments of Cu-ZnO thin films. The AFM study revealed that nanoparticles of Cu-ZnO films are varied from 225 to 74 nm with increasing process temperature from 650 to 800 degrees C. The relative intensity of E2(high) phonon increases with increase in the process temperature 650-800 degrees C. The photoluminescence spectra of Cu-doped ZnO films showed a strong ultraviolet emission peak centered at 392 nm and a strong blue emission peak centered at 450 nm. The calculated Tauc optical bandgap of Cu-ZnO thin films decreased from 2.72 to 2.22 eV, due to Cu incorporation in ZnO network with the increase with the process temperature. Moreover, the semiempirical electronic environments of Zn 2p3/2, O(1 s), and Cu (2p) core orbital are analyzed by the Origin software.