Preparation And Characterization Of Ultrafine ?-Ga₂O₃ Nanowires And Their UV Photodetectors

?-Ga₂O₃,as a third-generation semiconductor material with a high band gap(up to 4.9e V at room temperature)and a cutoff wavelength of roughly 250 nm,making it an ideal material for photodetectors.?-Ga₂O₃ materials come in a range of forms,including single crystals,thin films,and nanomaterials.Compared with thin film and bulk materials,nanomaterials have better crystallization quality and quantum size effect and other excellent properties.The smaller the size of the nanomaterial,the more significant the five nano-effects exhibited.This paper uses chemical vapor deposition(CVD)method to prepare ultra-fine?-Ga₂O₃ nanowires on low-cost quartz,silicon and sapphire substrates,and prepares ultraviolet detectors of different structures based on the grown nanowires,and studies the ultraviolet detection performance of the device:(1)Ultrafine?-Ga₂O₃ bridge nanowire with diameter of about 20 nm was grown in situ on sapphire(Al₂O₃)substrate by CVD method using gold as catalyst,and the ultraviolet detector with MSM structure was fabricated by using the grown bridge structure nanowires.The study found that the device has a good response to 254 nm ultraviolet light,and the light-dark current ratio of the device can reach 4.3×10~4 under 10 V bias.It was also found that the responsivity and external quantum efficiency of the detector decreased with the increase of optical power density,and when the light intensity was 100?W/cm~2,its response was 53.4 m A/W.In addition,the detector has a fast response to ultraviolet light,and the response time and recovery time are0.10 s and 0.21 s,respectively.This experiment provides ideas for the research of?-Ga₂O₃nanowire array devices.(2)A large-area,high-density ultrafine?-Ga₂O₃ nanowires with a diameter range of 10-40 nm were grown on the p-Si substrate by chemical vapor deposition method,and a self-driven?-Ga₂O₃ nanowire/p-Si heterojunction UV detector was made based on the prepared nanowires.It is found that the device exhibits good rectifying characteristics,and the photocurrent is 1.42?A and the light-to-dark current ratio is 6.09×10~2 under 254 nm light(550?W/cm~2)with 0 V bias,and the self-driving characteristics are exhibited.The response time and recovery time of the device are 0.42 s and 0.50 s,respectively.In addition,the responsivity of the device is 0.57A/W at 100?W/cm~2,and the external quantum efficiency is 278%.(3)The ultrafine?-Ga₂O₃ microwires were prepared by CVD method on a cheap quartz substrate,and the metal-semiconductor-metal(MSM)photoconductive detector based on?-Ga₂O₃ microwire was fabricated.Experimental results show that the diameter of the nanowires is distributed at about 10-20 nm.The UV detector based on ultrafine?-Ga₂O₃ microwire also has good UV detection and stability,and the light-dark current ratio is 8×10~3 under 254nm light.The responsivity of the device can reach 1.70 A/W,and the specific detection rate is 4.35×10¹²Jones.Meanwhile,the device has A fast response to UV,with response time of 0.12s and recovery time of 0.08 s.In this study,it is proved that?-Ga₂O₃ nanowires with large area and high density can be grown on low-cost quartz substrate,and the ultraviolet detector with excellent performance has been successfully prepared based on the nanowires,which provides ideas for the development of low-cost?-Ga₂O₃ UV detector.