| Because the UVC band(200-280 nm)radiation is completely absorbed by the earth’s atmosphere,it will not reach the ground.Therefore,this band is also called the sun-blind band.The photoelectric detector based on the Solar-blind band has the characteristics of extremely low background noise,high detection accuracy and strong anti-interference.With the development of today’s society,Solar-blind photoelectric detectors are widely used in ozone layer hole detection,missile tracking and early warning,high-voltage power grid detection,flame sensing lamps and other fields.However,traditional silicon-based detectors need to add filters to work under ultraviolet light,which limits the practical application of Solar-blind ultraviolet detectors.In recent years,with the extensive research of wide band gap semiconductor materials,the advantages of its large band gap width and high breakdown electric field strength become the basis for the preparation of solar blind photodetectors.Common wide band gap semiconductor materials such as AlGaN,ZnMgO,diamond,β-Ga2O3,etc.However,the preparation of AIGaN,MgZnO and diamond is complex and costly,which also hinders its application in the field of Solar-blind photoelectric detection.And the band gap of the monoclinic β phase Ga2O3 is 4.4-4.8 eV,and the corresponding wavelength is 258-280 nm.Due to its intrinsic diurnal blind light absorption characteristics,high breakdown field strength,high chemical stability,and thermal stability,it can continue to operate in harsh environments.At the same time,high quality and large size β-Ga2O3 single crystals can be obtained by using traditional melt growth technology.Thereforeβ-Ga2O3 is an ideal candidate material for Solar-blind photodetectors.In recent years,people are also based on β-Ga2O3 has been deeply studied in the field of sun-blind detection research,however,at present The Solar-blind photodetectors prepared by βGa2O3 usually have the problems of low response and slow response speed,so this paper aims to improve the performance of β-Ga2O3-based Solar-blind photodetectors,while considering the reduction of preparation cost,according to the energy band structure and conductive type of β-Ga2O3,the corresponding CuZnS,Cs3Cu2I5 thin films were explored and prepared to form high-quality heterostructures to realize the construction of high-performance Ga2O3 based self-powered solar-blind photodetectors.The main contents and results of the paper are as follows:I.Growth of CuZnS film and Preparation of CuZnS/β-Ga2O3 heterojunction devices In this paper,CuZnS thin films were grown on sapphire substrates by chemical bath deposition,and MSM devices were prepared to explore the relationship between the conductivity of CuZnS thin films and the content of added raw materials(Zn(CH3COO)2·2H2O)and CuSO4.From the I-V curve of MSM devices,the conductivity of CuZnS thin films gradually increased with the increase of the content.According to this law,CuZnS films with high conductivity were grown on β-Ga2O3 single crystal substrate,and CuZnS/β-Ga2O3 heterojunction photodetectors were prepared.Through the analysis of the photoelectric detection performance of CuZnS/βGa2O3 heterojunction device.The device shows a rectification ratio of up to 104 at ± 1 V.At the same time,the device shows high response and fast response speed at zero bias voltage.After 11 months under conventional storage conditions,the performance of the device has no attenuation.The device shows fast response speed(70/10 ms)and high light-dark current ratio(1893).The responsivity and detectivity are 48.01mA/W and 1.83×1012 Jones respectively.Ⅱ.Growth of Cs3Cu2I5 film and Preparation of Cs3Cu215/β-Ga2O3 heterojunction devicesIn this paper,the effect of anti-solvent chlorobenzene on the quality of Cs3Cu2I5 thin film during the spin-coating process was investigated.Through XRD,SEM,AFM,EDS tests,it was found that the addition of anti-solvent chlorobenzene during the spincoating process can effectively improve the crystal quality of the film and reduce the surface roughness of the film.Then the effect of the time of adding chlorobenzene as the anti-solvent on the quality of Cs3Cu2I5 film was further studied.Finally,it is concluded that high quality Cs3Cu2I5 films can be prepared by dropping the anti-solvent chlorobenzene at 20 s of the spin-coating process.According to this spin-coating process,Cs3Cu2I5/β-Ga2O3 heterojunction device can be prepared,and test the Photoelectric detection performance of Cs3Cu2I5/β-Ga2O3 heterostructure device.Cs3Cu2I5/β-Ga2O3 heterostructure device shows optical response at ±10 V bias voltage,with the lowest dark current of 7×10-13 A,the response of 0.548 mA/W,the detection rate of 1.01 ×1011 Jones,and excellent device performance.Because of type ⅡCs3Cu2I5/β-Ga2O3 heterojunction,the device has self-powered effect,and has the characteristics of fast response and high detection rate. |
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