Metal Rh Localized Surface Plasmon Enhanced AlGaN-based MSM Ultraviolet Photodetector

The ultraviolet photodetector work in the ultraviolet band and can identify target ultraviolet radiation signals under a natural low-noise background.Now it has been widely used in military and civilian fields such as missile guidance,ozone monitoring,ultraviolet imaging,and space communications.As one of the important members of the third-generation wide-bandgap semiconductor,AlGaN is regarded as the preferred material for ultraviolet photodetector due to its advantages such as a wide range of continuously adjustable wide-bandgap,high electron mobility and excellent thermal conductivity.However,the performance level of AlGaN-based ultraviolet photodetector is still to be improved compared with the mature ultraviolet photomultiplier tubes,and there is still a large room for improvement in practical application.To this end,we studied the localized surface plasmon(LSP)properties of metal Rh nanostructure,and used metal Rh nanoparticles to improve the performance of AlGaN-based metal-semiconductor-metal ultraviolet photodetector.The research work of this paper mainly includes the following two aspects:1.Research on the localized surface plasmon properties of metal Rh nanoparticle.The FDTD Solutions simulation method was used to construct the structural model of metal Rh nanoparticles,and the influence of key factors such as particle size,medium environment and geometric shape on the LSP characteristics of metal Rh nanoparticles was systematically studied.The simulation calculation results show that when the height of the cylindrical metal Rh nanoparticles is increased,the resonance wavelength of the LSP is blue-shifted,and the resonance intensity increases,and after the lateral size is increased,the resonance wavelength of the LSP is red-shifted,and the resonance intensity also increase;when increasing the dielectric constant of the environment where the cylindrical metal Rh nanoparticles are located,the resonance wavelength moves to the long wave direction,but the resonance intensity decreases accordingly;when the geometric shape of metal Rh nanoparticles is changed,the resonant wavelength of LSP changes due to the shape change.The in-depth study of the LSP characteristics of metal Rh nanostructures from the theoretical level has laid a certain foundation for practical exploration and applications.2.Research and preparation of AlGaN-based MSM ultraviolet photodetector based on metal Rh nanoparticles LSP enhancement.We explored the preparation process and conditions of metal Rh nano-structure,and fabricated orderly and regularly distributed metal Rh nanoparticle array by the self-assembly sphere template method,and introduced it into the AlGaN-based MSM photodetector,which effectively improve the performance of the ultraviolet photodetector.We believe that,on the one hand,due to the LSP far-field characteristics of metal Rh nanoparticles(light scattering enhancement effect),the effective absorption path of the absorber layer is increased,and the number of photogenerated electron-hole pairs is greatly increased;on the other hand,the LSP near-field characteristics of metallic Rh nanoparticles(local field enhancement effect)make the electron-hole pair separation speed faster,so the detection performance of the detector is improved.