Photoconductive UV Detectors Based on ZnO Films Prepared by Sol-Gel Method

Abstract

Highly c-axis oriented ZnO thin films were deposited on single crystal Si (111) substrates by sol-gel method. The photoconductive UV detectors based on ZnO thin films, being a metal-semiconductor-metal (MSM) structure with interdigital (IDT) configuration, were fabricated by using Au as contact metal. The characteristics of dark and photocurrent of the UV detector, the UV photoresponse of the detector were investigated. The linear current-voltage (I-V) characteristics under both forward and reverse bias exhibit ohmic metal-semiconductor contacts. Under illumination using monochromatic light with a wavelength of 365 nm, photo-generated current arrived at 44.89 μ A at a bias of 6 V. The detector exhibits an evident wide-range spectral responsivity and shows a trend similar to that in photoluminescence (PL) spectrum. PL spectrum of detector exhibits two peaks, one is the near band edge emission, and another is the deep-level emission in the visible region.