The Fabrication And Characterization Of High Performance Solar Blind Ultraviolet Detector Based On MgZnO Films With Mixed-structure

The solar blind UV detector has attracted intense study interests because of its wide application areas,such as missile warning,ozone hole monitoring,fire monitoring,ultra-high-speed ultraviolet communication,safe ultraviolet wireless communication,and so on.Compared with other wide bandgap semiconductor that used in solar-blind UV detector,such as Ga₂O₃,AlGaN,SnO₂,diamond,MgZnO has a wider bandgap?3.37 ev⁷.8 ev?adjustment range,a lattice-match substrate,and MgZnO is a rich and environmentally friendly material,which makas MgZnO as an ideal materials for high performance solar blind UV detectors.This paper would improve the performance of MgZnO based detector through relative system study on the UV response charateristics of mix-phase MgZnO thin films with different structure constitution,the introduce of Au/MgZnO/Ga dopoed ZnO/In heterojuction and FET structure UV detectors.The main results of this paper are listed as follows:?1?Through the great change in temperature,oxygrn pressure,oxygen flow rate and Mg composition,mix-phase MgZnO thin films with great difference in structure constitution were deposited on quartz substrates by PLD method.The performances of mix-phase MgZnO thin flms with great different structure constitution in UV detection was studied systematically.Mix-phase MgZnO detector that constituted by a slight amount of?200?cubic MgZnO mixed into large numbers of hexagonal MgZnO possess higher response?4.69 A/W?at 235 nm deep UV light.And because the high responsivity of the device is mainly due to the multiple tunneling process of photo generated carriers between cubic and hexagonal MgZnO under ultraviolet light condition,the mix-phase MgZnO own both high UV response and fast response and recovery speeds,the response time of the device is just?_r=0.18?s,the recovery times of which are just?_d1=12.3?s and?_d2=0.19 ms.?2?The Au/MgZnO/Ga-doped ZnO/In heterojunction UV detectors were fabricated,effect of different thickness Ga-doped ZnO thin film on the performance of the heterojunction UV detector were studied.Because of the obvious avalanche breakdown effect of the Au/MgZnO/Ga-doped ZnO?20nm?/In heterojunction UV detector under reverse bias,the response of the device at 254 nm solar-blind ultraviolet light reached 2.21 A/W under 2 V reverse bias voltage.And because of the internal electric field in the Au/MgZnO/Ga-doped ZnO?20 nm?/In heterojunction UV detector,the device could response at deep UV light without bias voltage,the response of of the device at 230 nm reach 2.55 mA/W.?3?Field effect transistor structure MgZnO UV detetcor was fabricated,within which MgZnO thin film was set as both UV sensitive and insulate material,and Ga doped ZnO thin film was set as active layer in this device.Because of the magnify function of FET structure detector,the response of the device reached 0.33 A/W at 254 nm ultraviolet light under lower-0.5 V gate and 3 V source-drain voltage condition.