Research On Preparation Of Zn Doped β-Ga₂O₃ Microwires And UV Detection Performance

β-Ga₂O₃ is a third generation III-VI ultra-wide-band gap oxide semiconductor material with a band gap width up to 4.9 e V and a corresponding cutoff wavelength of 253 nm.It has stable physical and chemical properties and is an ideal material for solar blind ultraviolet detectors.Due to the existence of intrinsic defects such as oxygen vacancy,β-Ga₂O₃ materials show N-type without doping.However,it is very difficult to achieve p-type hole conduction,which restricts the development ofβ-Ga₂O₃ optoelectronic devices.At present,the preparation of p-typeβ-Ga₂O₃ materials has been a difficult problem and a hot research direction at home and abroad.In this thesis,β-Ga₂O₃ microwires with different Zn doped contents were grown by chemical vapor deposition（CVD）without catalyst,and the morphology and structure of microwires were characterized.In addition,the photoconductive solar blind photodetectors based on single microwire,and single Zn-dopedβ-Ga₂O₃ microwire/Ti/Au Schottky junction photodetector were fabricated,and their UV detection performance was studied.The main research work of this thesis is as follows:（1）Large sizeβ-Ga₂O₃ microwires with different Zn-doped contents were prepared by chemical vapor deposition.The length of the microwires can be up to 1 cm.The shape of the microwires is standard quadrilateral prism,with a width of about 20μm and a thickness of about 10μm.The photoconductive solar blind UV detector based on single microwire was fabricated.The thermoelectric properties of the microwire were tested by the Seebeck effect and it was confirmed that the Zn-dopedβ-Ga₂O₃ microwires have p-type conducting properties.In addition,it was found that the photocurrent value,responsivity,and external quantum efficiency of the devices increased significantly with increasing Zn content.The light-to-dark current ratio of the device with the highest Zn doping was about 2.1×10³ under the 254 nm UV illumination with the light power intensity of 221μW/cm².Under weak UV illumination at 64μW/cm²,the responsivity and external quantum efficiency of the detector were 12.34 A/W and6036%,respectively.At the same time,a detector array is constructed based on the parallel connection of microwires with different root numbers.It is found that with the increase of the number of parallel microwires,the photocurrent value of the devices also increases.（2）A single Zn-dopedβ-Ga₂O₃ microwire/Ti/Au Schottky junction UV photodetector was fabricated by usingβ-Ga₂O₃ microwire with the maximum Zn content,and the UV photoelectric properties of the device were investigated.The results show that the Zn-dopedβ-Ga₂O₃ microwires can form a good Schottky contact with the metal Ti/Au,and the device has self-powered characteristics at 0 V bias.The light-to-dark current ratio of the device is 2.65×10³at 0 V bias under 254 nm UV illumination.When the light power intensity of 221μW/cm²,the responsivity（R）of the device can reach 3.34 A/W,the external quantum efficiency（EQE）is1634%,and the detectivity（D*）can be up to 2.2×10¹² Jones.In addition,after being stored at room temperature for three months,the device kept working normally.