Fabrication And Research Of Short-wave Infrared Upconversion Detector Based On Silicon Schottky Junction

Infrared imaging contains objective information that cannot be reflected by visible light imaging,and has important applications in many key fields such as biomedicine,homeland security,remote sensing,night vision,and semiconductor wafer inspection.However,the detection wavelength of the current infrared upconversion detector is mainly concentrated in the near-infrared light range,and the upconversion efficiency and sensitivity are relatively low,and the most mature infrared imaging technology also has the problem of complex preparation process and high cost.Silicon-based photodetectors have the advantages of high efficiency,low power consumption and stable performance.However,the indirect band gap and limited absorption range of silicon restrict the application of silicon-based photodetectors.In recent years,the emergence of nanostructures and silicon heteroj unctions has enabled silicon-based photodetectors to break through the absorption range limitation,and high-performance silicon-based infrared upconversion detectors need to be further explored.In view of the mentioned challenges,this paper focuses on the following research work:1.Broad-spectrum short-wave infrared upconversion detector based on pyramid structure PtSi Schottky junctionIn this work,the Pt film was deposited on the silicon substrate by magnetron sputtering technology,treated by annealing process,and pyramid structures were introduced to construct a high-performance PtSi heterojunction,which effectively promoted the separation of photogenerated carriers.At the same time,the introduced pyramid micro-nanostructure not only enhances the absorption efficiency of light by the detector,but also provides a channel for the fast transmission of photogenerated carriers and improves the collection efficiency of carriers.Finally,the pyramid-structured PtSi heterojunction photodetector has a high responsivity of 1.2×10-2 A/W and a spectral response in the range of 1550 nm,breaking through the spectral response limit of traditional Si-based photodetectors.On this basis,the PtSi Schottky junction short-wave infrared upconversion detector was constructed by combining the PtSi photodetector with OLED by introducing focal plane array technology.The device achieves upconversion luminescence under 1550 nm infrared irradiation with a maximum brightness of 12.7 cd/m2,and high-resolution imaging of 1310 nm infrared light of the device was realized.This work provides a new strategy and approach for high-performance and low-cost broad-spectrum shortwave infrared imaging by constructing Si-based infrared upconversion detectors.2.Weak-light short-wave infrared upconversion detector based on surface plasmon structure Au/Si Schottky junctionIn this work,Uniform height si array pyramid were prepared by combining dry etching and wet etching processes,and using this as a substrate,a well-coated Al2O3 interface passivation thin layer was prepared by atomic layer deposition technology.Finally,a high-performance Au/Si heterojunction was constructed by using the surface plasmon structure.Due to the design of the trapping structure,interface engineering,and surface plasmon structure,the Au/Si heterojunction photodetector exhibits high responsivity(9.8×10-2 A/W),high linear dynamic range(110 dB)and high specific detectivity(2.24×1013 Jones).The excellent performance of the device is mainly attributed to three aspects:(ⅰ)The Si array pyramid improves the absorption efficiency of the photodetector to light;(ⅱ)The surface plasmon structure makes the generated thermal electrons gather at the top of the pyramid,which improves the photoelectric conversion efficiency of the device;(ⅲ)The introduction of the interface passivation layer Al2O3 inhibits the recombination of carriers at the Au/Si interface and improves the quality of the heterojunction.Later,the Si-based infrared upconversion detector introduced focal plane array technology,which realized the upconversion luminescence in the 1550 nm shortwave infrared range and the high-quality upconversion imaging in the 1310 nm infrared range.In the 1064 nm NIR range,the device’s highest upconversion efficiency(3.3%)is consistent with that of the Ⅲ-Ⅴ upconversion detector.At the same time,the upconversion detector also has the ability to image in weak-light conditions,and can recognize 30 μW/cm2 of weak light under 1064 nm near-infrared irradiation.The highperformance Au/Si Schottky junction upconversion detector is constructed by using the surface plasmon structure,which provides a new idea for the realization of weak-light short-wave infrared imaging.