Research On The Preparation And Properties Of SiC/in Situ Graphene/Ga₂O₃ Sandwich Structure UV Detectors

Solar-blind UV photodetectors have been widely used in optical communication,3D printing,astronomical research,biomedicine,military applications and other fields.At present,solar-blind UV photodetectors based on silicon-based inductive coupling devices and micro-channel plate devices are widely used in the market.Among them,silicon-based inductive coupling devices will be interfered by background light,and they need to be used with solar-blind filters.,the use cost is high;the structure of the microchannel plate device is relatively complex,and it can only work under extremely high bias voltage.The forbidden band width of gallium oxide is 4.9 e V,which is intrinsically responsive to ultraviolet light in the solar blind area and has a very high responsivity,which is very suitable for solar blind ultraviolet light detection.However,the low electron mobility and the incomplete coverage of detection frequency bands limit the response speed and bandwidth of gallium oxide UV devices.Combining the high mobility properties of graphene,the UV detection properties of Si C and the high solar blind response ofβ-Ga₂O₃,it is expected to prepare a UV photodetector with fast response speed and wide-spectrum detection.In this study,the fabrication process and detection characteristics of UV photodetectors based on 4H-Si C/graphene/β-Ga₂O₃ heterostructures were systematically studied in order to realize high-performance gallium oxide-based UV detectors.The details are as follows:Firstly,the physical properties of gallium oxide and silicon carbide epitaxial graphene are theoretically discussed,and the structure model ofβ-Ga₂O₃/graphene/4H-Si C three-layer sandwich material is established and numerically simulated.The simulation results show that compared with Forβ-Ga₂O₃/4H-Si C structure,β-Ga₂O₃/graphene/4H-Si C three-layer sandwich structure,due to the addition of graphene,the photoresponse characteristics are significantly improved.Secondly,graphene was epitaxially grown on the Si surface of Si C by pyrolysis of Si C,and a layer ofβ-Ga₂O₃ was epitaxially grown on the surface of Si C epitaxial graphene by PLD pulsed laser deposition method to completeβ-Ga₂O₃/graphene./4H-Si C three-layer sandwich structure.The characterization results of XRD diffraction and Raman spectroscopy show that both epitaxial graphene and gallium oxide in the prepared structure have good quality,and epitaxial graphene is single-layer graphene.The etching process of gallium oxide and graphene in the three-layer structure and the preparation process of gallium oxide ohmic contact were explored,and the solar-blind UV detector based on theβ-Ga₂O₃/graphene/4H-Si C three-layer sandwich structure was finally completed.Finally,systematic I-V,I-T and other optoelectronic tests were carried out on the preparedβ-Ga₂O₃/graphene/4H-Si C solar-blind UV detector.The test results show that the related process can well complete the solar-blind UV detector based on the three-layer sandwich structure.The preparation of the detector,and the obtained device has stable photocurrent response and spectral response capability.A comparative study of UV detectors with three-layer sandwich structure andβ-Ga₂O₃/4H-Si C structure found that the performance improvement of in-situ graphene on solar-blind photodetectors is mainly reflected in two aspects.On the one hand,the high mobility of graphene increases On the other hand,the strong thermal conductivity of graphene reduces the channel temperature of the device,and its good flexibility reduces the stress caused by the lattice difference between the two semiconductor materials and reduces the dislocation density,thereby reducing the dislocation density.The dark current of the device is reduced.