High Responsivity MgxZn1-xO Based Ultraviolet Photodetector Fabricated by Dual Ion Beam Sputtering

MgxZn1-xO (x = 0.05, 0.15 and 0.20) based metal-semiconductor-metal ultraviolet (UV) photodetectors were fabricated on Si substrate using dual-ion-beam sputtering. The performances of fabricated photodetectors were studied by current-voltage, spectral photoresponse, and temporal response measurements. The values of peak responsivity of photodetectors were 0.4, 0.31, and 0.27 A/W with corresponding external quantum efficiency of 146%, 110%, and 105% for x = 0.05, 0.15 and 0.20, respectively. The cutoff wavelength and UV/visible rejection ratio of fabricated photodetectors decrease over 360-330 nm and 341.8-115.3, respectively, with increase in Mg concentration. The variation in specific detectivity and noise equivalent power with Mg concentration variation is also reported.