Metal-semiconductor-metal 4H-SiC Hot-electron Photodetector Based On Surface Plasmon Polaritons Effect

Metal-semiconductor-metal photodetectors have received extensive attention in many fields such as communications,sensing,and guidance etc.due to the high responsivity,low dark current and easy integration.As a representative of the thirdgeneration semiconductor,Si C has obvious advantages such as high critical breakdown electric field and high electron mobility compared with the first and second generation traditional semiconductor materials,making it to be an excellent semiconductor material for manufacturing high-voltage,high-temperature,and radiation powerresistant semiconductor devices.However,as a wide band gap semiconductor,Si C can only work in the ultraviolet band,which limits the application of this material to a great extent,Surface Plasmon Polaritons(SPP)hot electron effect excited by metal nanostructures can effectively capture incident light,and excited hot carriers which can effectively improve the detectivity and broaden the detection spectrum has be deemed as a feasible method to improve the performance of photodetectors.Reasonably combining metal nanostructures with Si C can produce a MSM hot-electron photodetector with a wider detection spectrum and higher detection performances.In this dissertation,we used the third generation semiconductor material Si C as research object,and the methods of magnetron sputtering and thermal annealing were also used to prepare MSM type hot electronic photodetector,the main works as follows:(1)First,the planar MSM type 4H-Si C photodetectors based on different doping types of 4H-Si C wafers is studied,and we found that the device prepared by intrinsic4H-Si C wafers has the best performance.Then,Au Nanoparticles(Au NPs)were prepared on 4H-Si C wafers surface by thermal annealing method,and their effects on the performances of metal /4H-Si C hot-electronic photodetector were also investigated.At the same time,the optical and electrical properties of the photodetector were optimized,and finally,the detection wavelength range of 4H-Si C photodetector is expanded from ultraviolet to visible and even reached near-infrared band under the effect of surface plasmon hot electronic effect.Compared with the Au NPs-free control device,the light absorption,transient photocurrent,responsivity and EQE are increased by 19.6 times,28 times,26 times,21 times and 36 times,respectively at 660 nm.(2)On the basis of the previous work,a vertical MSM type Schottky junction photodetector is prepared.In this work,we mainly studied the influence of transparent electrodes with different metal materials on the performances of the vertical MSM type metal /4H-Si C photodetectors.It is found that the transparent electrodes prepared by different metal materials have different effects on the device,and the Au transparent electrode with the thickness of 15 nm has the best performance.Then Au nanoparticles were also added on the surface of 4H-Si C to prepare a MSM type hot-electron photodetector with vertical structure.The absorption spectrum of the device was also obviously expanded with the addition of Au nanoparticles,and the transient photocurrent increased by an order of magnitude at 660 nm.This work will lay a foundation for MSM type metal /4H-Si C Schottky junction hot-electron photodetector with vertical structure in the future.In conclusion,this dissertation proposes a strategy of using SPP effect to effectively broaden the detection spectrum of 4H-Si C photodetector by adjusting the parameters of Au nanoparticles.In addition,by further optimizing the device structure parameters,the detection performance of the device has been greatly improved.The research results of this dissertation provide some research ideas for effectively improving the performance of 4H-Si C photodetector in the future.