ZnO-based interdigitated MSM and MISIM ultraviolet photodetectors

Abstract

The paper reports the fabrication and characterization of ZnO-based interdigitated metal–semiconductor–metal (MSM) and metal–insulator–semiconductor–insulator–metal (MISIM) ultraviolet photodetectors. The ZnO thin film was grown on a p-type Si ⟨1 0 0⟩ substrate by the sol–gel technique. With applied voltage in the range from −3 to 3 V we estimated the contrast ratio, responsivity, detectivity and quantum efficiency of the photodetectors for an incident optical power of 0.1 mW at 365 nm ultraviolet wavelength. The I – V characteristics were studied and the parameters such as ideality factor, leakage current and barrier height were extracted from the measured data. For Au/Cr/SiO 2 /ZnO/SiO 2 /Al (MISIM) structure the product ( m χ) of the tunnelling effective electron mass ( m ) and the mean tunnelling barrier height (χ) was also extracted.