A three-dimensional electromagnetic field model has been developed to study the photon capture properties of gradient band-gap AlxGa1-xN nanomaterials with built-in electric field using COMSOL Multiphysics commercial software based on finite element numerical simulation. Based on the phototrapping mechanism and the concept of radial mode resonance absorption, we studied AlxGa1-xN nanomaterials with different cross-section shapes and Al component distributions to obtain broad-band and omnidirectional light absorption in the ultraviolet band. In this process, based hexagonal periodic arrangement, we simulated and analyzed the optical responses of cones, hexagonal pyramids and hexagonal prisms structure, including optical absorption, quantum efficiency, electric field distribution and generation rate distribution. The results show that the non-uniform pyramid structure can effectively enhance the optical absorption efficiency at FR = 0.9. The photon generation rate of the pyramid nanostructure is mainly distributed in the cathode nanostructure part, which is significant for improving the emission efficiency of cathode electrons. In addition, we investigated the optical properties of AlxGa1-xN nanostructures by changing the distribution of Al component and the thickness of different sublayers. As a result, the prism structure achieves optimal optical absorption and quantum efficiency when the Al component ranges from 0 to 0.75. Although a strict three-dimensional AlGaN NWAs array model has been established in this work, it is still necessary to demonstrate the experimental results. In the future research, we will experimentally study the effect of different geometric shapes on UV photocathode.

建立了三维电磁场模型，利用COMSOL Multiphysics商业软件基于有限元数值模拟研究了具有内置电场的梯度带隙AlxGa1-xN纳米材料的光子捕获特性。基于光阱机理和径向模式共振吸收的概念，我们研究了具有不同横截面形状和Al成分分布的AlxGa1-xN纳米材料，以获得紫外波段的宽带和全向光吸收。在此过程中，我们基于六边形的周期性排列，模拟并分析了圆锥，六边形金字塔和六边形棱镜结构的光学响应，包括光吸收，量子效率，电场分布和生成速率分布。结果表明，非均匀金字塔结构可以有效提高FR = 0.9时的光吸收效率。锥体纳米结构的光子产生速率主要分布在阴极纳米结构部分，这对于提高阴极电子的发射效率具有重要意义。此外，我们通过改变Al组分的分布和不同子层的厚度来研究AlxGa1-xN纳米结构的光学性质。结果，当Al组分的范围为0至0.75时，棱镜结构实现了最佳的光吸收和量子效率。尽管已经在这项工作中建立了严格的三维AlGaN NWAs阵列模型，但是仍然有必要证明实验结果。在未来的研究中，