Ultraviolet photoconductive detector based on Al doped ZnO films prepared by sol–gel method

We report a study on the fabrication and characterization of ultraviolet photodetectors based on ZnO:Al films. Using sol–gel technique, highly c-axis oriented ZnO films with 5 mol% Al doping were deposited on Si(1 1 1) substrates. The photoconductive UV detectors based on ZnO:Al thin films, having a metal–semiconductor–metal (MSM) structure with interdigital (IDT) configuration, were fabricated by using Au as a contact metal. The characteristics of dark and photocurrent of the UV detector and 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 350 nm, photo-generated current was measured at 58.05 mA at a bias of 6 V. The detector exhibits an evident wide-range spectral responsivity and shows a trend similar to that in transmittance and photoluminescence spectrum