Effect of thermal annealing on the structural and optical properties of CuO nanocrystals formed on Al2O3 substrates using spin coating

Abstract

Cupric oxide (CuO) nanocrystals were formed on Al2O3 substrates by spin-coating and thermal treatment methods. X-ray photoelectron spectroscopy profiles showed that the CuO nanocrystals were formed on the Al2O3 substrates and that the binding energy of the peak corresponding to the Cu 2p(3/2) decreased with an increase in the annealing temperature. X-ray diffraction (XRD) patterns showed that the XRD peak intensity corresponding to the (200) K-alpha diffraction peak for the CuO nanoparticles on the Al2O3 substrates increased with an increase in the annealing temperature. Scanning electron microscopy images showed that the average diameter and the density of the CuO crystalline nanoparticles formed on Al2O3 substrates increased with an increase in the annealing temperature due to the coalescence of the CuO nanoparticles. Photoluminescence spectra at 300 K showed that a peak position related to the band edge emissions shifted to the small energy side with an increase in the annealing temperature.