High performance solar-blind ultraviolet photo detector based on mixed-phase MgZnO thin film with different interfaces deposited by PLD method

Abstract

MSM structure UV detectors were fabricated on mixed-phase MgZnO thin films with (200) cubic MgZnO/hexagonal MgZnO and (111) cubic MgZnO/hexagonal MgZnO interfaces by PLD method. Under 25 V bias voltage, the maximum responsivity of the mix-phase MgZnO based detector with (002) cubic MgZnO/hexagonal MgZnO interfaces reached 8 A/W at 256 nm because of 3809% internal gain of the detector at solar-blind UV light, which is two order of magnitude bigger than the detector with (111) cubic MgZnO/hexagonal MgZnO interfaces. The higher density of interface states between (200) cubic and hexagonal MgZnO grains in the mix-phase MgZnO thin film is main reason for its big internal gain and high solar-blind UV response. The Idark of the mixed-phase MgZnO based detector with (111) cubic MgZnO/hexagonal MgZnO interfaces is much smaller and the Ilight/Idark of which is higher because of the higher interfaces barrier at (111) cubic MgZnO/hexagonal MgZnO interfaces, so the detector could effectively detect faint solar-blind UV signal more under strong noise background.