Fabrication and characterization of ZnO photodetectors with high gain

Abstract

We report fabrication and characterization of MSM UV photodetector based on Pd/ZnO thin film. The ZnO thin film was grown on glass substrate by thermal oxidation of pre-deposited zinc films by vacuum deposition technique. With applied voltage in the range from -3 V to 3 V we estimated the contrast ratio, responsivity, detectivity for an incident radiation of 0.1 mW at 365 nm wavelength. Our device exhibited a high gain which is attributed to the hole trapping at semiconductor-metal interface. I-V characteristics were studied by using microprobe arrangement. The parameter such as ideality factor, leakage current, resistance-area-product and barrier height were extracted from the measured data. The surface morphological and the structural properties of the thin film were studied by atomic force microscope. Copyright © 2009 American Scientific Publishers All rights reserved.