Effect of thickness on the optical properties of ZnO thin films prepared by pulsed laser deposition technique (PLD)

Abstract

Zinc Oxide (ZnO) thin films of different thickness were prepared on ultrasonically cleaned corning glass substrate, by pulsed laser deposition technique (PLD) at room temperature. Since most application of ZnO thin film are certainly related to its optical properties, so the optical properties of ZnO thin film in the wavelength range (300-1100) nm were studied, it was observed that all ZnO films have high transmittance (˃ 80 %) in the wavelength region (400-1100)nm and it increase as the film thickness increase,using the optical transmittance to calculate optical energy gap (Egopt) show that (Egopt) of a direct allowed transition and its value nearly constant (~ 3.2 eV) for all film thickness (150, 180, 210, and 240) nm,so Zn0 thin films were used as a transparent conducting oxide (TCO) in various optoelectronic application such as a window in a thin film solar cells.