Room Temperature Photoluminescence and Optical Parameters of Micro Rods ZnO Thin Films Deposited on Silicon Substrates

Abstract

Micro structured zinc oxide (ZnO) is of potential use in solar cells, solid state gas sensors, and other optoelectronic devices. For the advancement of these technologies, a comprehensive understanding of these materials' optical characteristics is considered essential. Using the spray pyrolysis (SP) method, thin films of ZnO micro rods are deposited from aqueous zinc chloride solution on silicon substrates held at 350±5 °C. The films have been studied using the data acquired from the X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), reflectance and photoluminescence (PL) spectroscopy. Hence, the XRD and SEM confirmed the films' hexagonal phase and revealed the tapered ends of the hexagonal rods. The optical parameters including the refractive index, extinction coefficient, absorption coefficient, real and imaginary dielectric constants, conductivity, and the energy loss are all deduced from the reflectance spectra. Finally, the photoluminescence spectra of the studied samples are measured at room temperature using two excitation wavelengths: 300 and 365nm. As such, the obtained results confirmed the quality of the prepared films and allowed proper determination of their respective optical characteristics.