Influence of Al doping on microstructure, morphology, optical and photoluminescence properties of pyrolytic ZnO thin films prepared in an ambient atmosphere

Abstract

Zinc oxide (ZnO) and aluminium (Al) doped zinc oxide (AZO) thin films have been fabricated by spray pyrolysis technique in normal atmospheric condition. Samples of different Al-concentrations (0–5% Al) were deposited at 350 °C onto glass substrate to study the structural, morphological, optical and photoluminescence properties. X-ray diffraction study confirms that the films are polycrystalline having hexagonal structure. SEM images show that the films have rope and tube like morphology. Optical properties, such as transmittance, optical band gap, extinction coefficient, refractive index, optical conductivity, dielectric constants and electron energy loss functions were analyzed and discussed. Results show that the optical parameters have been changed significantly with Al-doping concentration. The photoluminescence spectra indicate that the PL peaks originated from deep level emissions (DLE) with different intensities for ZnO and Al-doped ZnO films.