Study On The Fabrication And Optoelectronic Properties Of Photodetector Based On SnO₂/Textured Silicon Heterojunction

In recent years,surface microstructure engineering strategies have been used to improve the performance of photovoltaic devices such as large-scale solar cells.With the development of silicon-based solar cells,their surface microstructures are also rapidly enriched,including porous silicon,positive pyramid,inverted pyramid,V-shaped groove structure,etc.These textured structures can effectively improve the light capture ability of silicon wafers and improve the utilization of light.As a photoelectric device,the silicon-based photodetector has a weak ability to detect ultraviolet light,which restricts its application as a broad-spectrum photoelectric detector.As a wide-band gap semiconductor,tin oxide（SnO₂）has attracted more and more attention in ultraviolet photoelectric detection and photovoltaic devices due to its high optical transparency,excellent conductivity,excellent physical and chemical stability,etc.In this paper,we combine the silicon chip with surface trapping structure and the tin oxide semiconductor film with excellent material properties to prepare the textured silicon and SnO₂heterojunction photodetector by taking advantage of the strong light absorption ability of the textured structure and the excellent performance of SnO₂in the ultraviolet band.In this paper,three kinds of surface textured Si wafers（upright pyramid,inverted pyramid,V-groove groove）were prepared by the standard surface wet etching process in the photovoltaic industry to reduce their reflectivity,improve their light absorption ability and spectral utilization;On this basis,SnO₂/textured silicon heterojunction device was prepared and its photoelectric detection performance was studied.The first chapter mainly introduces the stextured structure and its trapping characteristics,the wide band gap semiconductor tin oxide,and the research progress of silicon-based photodetectors,and summarizes the development status of silicon-based photodetectors.The second chapter introduces the experimental instrument and its principles,the device preparation process,the device performance characterization methods,and the etching processes of the silicon surface.In chapter 3,the performance of heterojunction photodetector（SnO₂/T-Si PD）on SnO₂/textured silicon substrate is studied.The prepared heterojunction photodetector on SnO₂/textured silicon substrate has a response in the wide spectral wavelength range of300-1000 nm,with a response over 0.4 A/W.At 1 V bias,the best response of SnO₂/T-Si photodetector at 800 nm is 1.88 A/W,which is higher than that of similar commercial devices.In chapter 4,the heterojunction polarization photodetector（PD）of SnO₂/V groove textured silicon substrate is studied.Based on the anisotropic characteristics of V-groove textured structure,it is directly combined with tin oxide to realize omnidirectional and polarized light detection.The fifth chapter summarizes the contents of the full text and the innovation of the paper,and puts forward the prospect of relevant research.