Characterization of UV photodetectors with MgxZn1−xO thin films

In this study the metal–semiconductor–metal (MSM) structure ultraviolet (UV) photodetectors (PDs) based on MgxZn1−xO thin films were fabricated. The MgxZn1−xO thin films were grown on glass substrates by sol–gel method. The results show that the optical absorption has a blue shift and higher transmittance with increasing Mg dopant. The optical band gap were modified by 3.28–3.52 eV, which corresponded to x = 0 and x = 0.16. For a 10 V applied bias, the dark currents of the MgxZn1−xO MSM–PDs were 637 nA (x = 0) to 0.185 nA (x = 0.16) and showed good Schottky contacts. This UV–visible rejection ratio of the MgxZn1−xO UV PDs at x = 0, 0.16, 0.21 and 0.33 were 18.82, 35.36, 40.91 and 42.92, respectively.