单根磷掺杂β-Ga_(2)O_(3)微米线日盲紫外探测器性能

Performance of A Single Phosphorus-dopedβ-Ga_(2)O_(3)Microwire Solar-blind Ultraviolet Photodetector

β-Ga_(2)O_(3)是一种新兴的超宽带隙半导体材料,由于具有4.9 eV的带隙、较高的击穿电场(8 MV/cm)及较高的热稳定性和化学稳定性等优良特性,使其成为一种很有前途的半导体材料,在高功率电子器件、气体探测器和日盲紫外(UV)光电探测器等领域有着较为广阔的应用前景。本文采用化学气相沉积法(CVD)生长出大尺寸的厘米级磷掺杂β-Ga_(2)O_(3)微米线,并对微米线的表面形貌、晶体结构和成分进行了研究,发现微米线的长度可达0.6~1 cm,直径约为40μm。基于生长出的磷掺杂β-Ga_(2)O_(3)微米线制作了单根磷掺杂微米线的日盲紫外探测器,研究表明未掺杂和磷掺杂β-Ga_(2)O_(3)微米线对254 nm紫外光都具有良好的响应,其中磷含量为2.3%微米线制作的器件,其光电探测性能最好。该磷含量微米线器件在光功率550μW/cm^(2)时,其光电流为3.1μA,暗电流为1.56 nA,光暗电流比约为2×10^(3),上升和下降时间分别为47 ms和31 ms。当光功率为100μW/cm^(2)时,器件的光响应度和外量子效率最大,分别为6.57 A/W和3213%。此外,还对器件的紫外探测机理进行了研究。

Recently,ultraviolet(UV)photodetectors have aroused the widespread concern of researchers around the world for their wide applications in UV radiation detection,missile warning,flame detection,ozone monitoring,and environmental monitoring.Most of the solar-blind photodetectors have been realized based on the wide bandgap semiconductor materials,such as ZnMgO,AlGaN,diamond andβ-Ga_(2)O_(3).Compared with these semiconductor materials,β-Ga_(2)O_(3)is an emerging wide bandgap semiconductor that has attracted a large amount of interest due to its ultra-large bandgap of 4.9 eV in the solar-blind range,a high breakdown field of 8 MV/cm,and high thermal stability and chemical stability.In addition,the study shows that the impurity doping can significantly improve the electrical properties ofβ-Ga_(2)O_(3)materials.In this paper,large-scale centimeter-level phosphorus-dopedβ-Ga_(2)O_(3)microwires were grown by chemical vapor deposition method without any catalyst.The high purity Ga2O3,P2O5,graphite powders and O2 were used as the source materials and reactant gas for the microwires growth.The surface morphology,crystal structure and composition of the microwires were studied.It was found that the length of the microwire about was 0.6-1 cm and the diameter was about 40μm.In order to study the UV sensing characteristics of photodetector,we fabricated a metal-semiconductor-metal(MSM)structure solar-blind ultraviolet detector based on a single phosphorus dopedβ-Ga_(2)O_(3)microwires.The results show that both the undopedβ-Ga_(2)O_(3)microwires and phosphorus dopedβ-Ga_(2)O_(3)microwires have good responses to 254 nm UV light,and the photocurrent value of the device made of the microwire with phosphorus content of 2.3%is the highest.Further photoelectric test of the phosphorus doped device shows that when the optical power is 550μW/cm^(2),the photocurrent is 3.1μA,the dark current is 1.56 nA,the photo-to-dark current ratio is about 2×10^(3),the rise and fall time are 47 ms and 31 ms,respectively,and the responsivity reaches 2.8 A/W.When the optical power is 100μW/cm^(2),the optical responsivity and external quantum efficiency of the device are the largest,which are 6.57 A/W and 3213%,respectively.Meanwhile,the UV detection mechanism of the device was studied.