Fabrication And Properties Of CuSCN/Ga₂O₃ Thin Film Heterojunction Photodetector

Ultraviolet photodetectors are widely used in space optical communication,environmental monitoring,missile guidance and flame detection.Gallium oxide(Ga2O3),as the third generation semiconductor material,has a very wide band gap(4.2-5.3 eV),good reliability and availability.It is very suitable for ultraviolet(UV)photoelectric detection and can meet the needs of solar blind area UV detection.CuSCN has a wide direct band gap(3.9 eV),high hole mobility and stable chemical properties.And it is often used as p-type semiconductor materials.CuSCN is also suitable for photodetectors because of its excellent structure and optical,electrical,chemical and thermal properties.CuSCN and Ga2O3 are used to form the heterojunction.The deep ultraviolet photoelectric detector based on the heterojunction has a certain application potential.The main work of this paper is to prepare gallium oxide(MetalSemiconductor-Metal)MSM photodetectors and CuSCN/Ga2O3 heterojunction photodetectors,and test and analyze their photoelectric properties.The main research results are as follows:1.In this paper,Ga2O3 film was prepared on sapphire(Al2O3)substrate by metal-organic chemical vapor deposition(MOCVD),and gallium oxide MSM photodetector was prepared by DC magnetron sputtering Ti/Au electrode.Ga2O3 film was characterized by XRD.The UV-vis absorption spectra of the film were measured,and the photoelectric properties of the device were also tested.The device has high sensitivity under ultraviolet light with wavelength of 254 nm and light intensity of 1000 μW/cm2.When the bias voltage is 5 V,the light-dark current ratio(PDCR)of the device is 4.55×103,and the rise time χ2 is 0.38 s and 0.07 s,and the decay time id is 0.24 s and 0.29 s.2.CuSCN thin film was further prepared on Ga2O3 thin film by spincoating method to form CuSCN/Ga2O3 PN heterojunction.Ti/Au point electrode was deposited by DC magnetron sputtering to prepare a photodetector based on the heterojunction,and its photoelectric properties were tested.The thin films were characterized by XRD,SEM,UV-vis absorption spectrum and transmission spectrum.The results show that the device has high sensitivity and good self-powered performance under ultraviolet light with wavelength of 254 nm and light intensity of 1000μW/cm2.At-5 V,the photo-dark current ratio(PDCR)is 6.07×103,and the light responsivity(R)is 5.5 mA/W.The detectivity(D*)is 3.8×1011 cm·Hz1/2·W-1 Jones,the rejection ratio(R270nm/R600nm)is 4.33×103,and the self-powered electric performance is good.The rise time of the device is 0.45 s and 3.80 s,and the decay time is 0.26 s and 0.26 s,respectively.The CuSCN/Ga2O3 heterojunction material has certain application potential in realizing self-powered and high-performance deep ultraviolet photodetectors.