Transient Photoconduction and Relaxation Photocurrent of ZnO Thin Films Produced by Pulsed Laser Deposition

Abstract

This paper presents the results of a photoelectric study of cobalt-doped zinc oxide thin films. Layers were grown by pulsed laser deposition on Si, glass, and SiO2/Si substrates. The crystal structure of the layers was determined by X-ray diffraction methods. The time dependence of the photoconductivity was studied with zone-band excitation, excitation in the contaminant absorption region, and excitation in the dark. The analysis of the photoconductivity dynamics on the duration of the excitation pulse was carried out for the structural layers. The influence of the concentration of deep traps on the form of the photoconduction and long-term relaxation processes is evaluated. ZnO thin films produced by pulsed laser deposition are suitable for photosensors because of their photosensitivity in the UV spectral range.