Development Of High-performance Gallium Oxide-based Photodetector

In recent years,the research on ?-Ga₂O₃ solar-blind ultraviolet photodetection technology has developed rapidly.As a new type of ultra-wide bandgap semiconductor material with a band gap of 4.9eV,?-Ga₂O₃ has superior chemical and physical properties.Such as light transmittance,high chemical stability,high breakdown electric field,strong anti-radiation ability,etc.It is the best natural material for preparing ultraviolet photodetectors.Therefore,in recent years,ultraviolet photodetectors using ?-Ga₂O₃ as the preparation material have received widespread attention of researchers.The preparation technology of ultraviolet photodetectors using ?-Ga₂O₃ as the preparation material has also made great achievements.But its shortcomings such as low response and slow response speed have not been solved,which seriously restricts the use of gallium oxide in application in the field of photoelectric detection.Based on this problem,this paper mainly starts from two aspects of optimizing the device structure and modifying the device,exploring effective methods to improve the photoelectric performance of the photo detector.The main research content and main conclusions of the paper are as follows:1)Using pulsed laser deposition technology(PLD)to epitaxial ?-Ga₂O₃ film on a doubleprofile sapphire substrate.The crystal structure,surface morphology,oxygen vacancy concentration and optical band gap of the film were characterized and tested.After confirming that the film is of good quality,a photodetector with MSM structure was prepared using the film and its photoelectric performance was tested.The results show that the photodetector exhibits good "sun blindness" characteristics.Under 15V applied voltage,the spectral responsivity of the detector reached 16 A/W.The detection rate exceeds 1012 Jones,the UV/Visible suppression ratio exceeds 103,and the response time is 0.26 s/0.21s under the irradiation of 254 nm wavelength light.2)In UV photodetectors among MSM structure on the basis of added metal platinum(Pt)nanoparticles to the decoration.In this thesis nanoparticles was studied by simulation and experiment of different size effect on the performance of photoelectric detector.The final results show that metal nanoparticles diameter is about 40 nm.The optimal detector detector performance rate reached 1.3 x 1011 Jones,ultraviolet visible light inhibition ratio of more than 104.3)Finally,a CuI film was prepared on the ?-Ga₂O₃ film by vacuum thermal evaporation technology.After characterizing the Cul film's crystal structure,surface morphology,oxygen vacancy concentration,and optical band gap,the film was prepared based on the characterization test.CuI/?-Ga₂O₃ heterojunction photodetector and its photoelectric performance have been tested.The results show that under-15V bias.The dark current of the detector is only 13 nA.The light to dark ratio reaches 33,and the spectral responsivity Reached 31.5A/W.The linear dynamic range is 58 dB,and the detection rate reaches 1.3×1011 Jones.The ultraviolet/visible light spectral response suppression ratio exceeds 104.