A Correlative Investigation of Photoconductive Behaviour of Bare and Al-Doped ZnO Thin Films

Abstract

Zinc Oxide (ZnO) nanoparticles exhibit a wide range of applications owing to their unique properties such as low cost, non-toxicity, abundance in nature and suitability for doping. In the present study, ZnO and Aluminium doped Zinc Oxide (Al-ZnO) nanoparticle thin films were prepared on FTO glass substrate by sol-gel and spin coating methods. The structural and morphological characteristics of the undoped and Al-doped ZnO nanoparticles were examined by X-ray Diffraction (XRD) and High Scanning Electron Microscope (HR-SEM) analysis, respectively. The XRD studies revealed the hexagonal wurtzite structure of the as-synthesized ZnO samples and the crystallite size was estimated using Scherrer’s formula to be 28 and 30 nm respectively, in the case of the undoped and doped ZnO nanoparticles. The average particle sizes in nanoscale were analysed using FESEM and found to be 38 nm and 42 nm for the bare and doped samples. The surface area of the as-synthesised particles were correspondingly estimated as 46 m2/g and 25 m2/g and their relative pore volume and diameter were determined using BET analysis. The field dependent photoconductivity of Al-ZnO shows a significant increase as against the bare ZnO.