量子阱红外探测器双面金属光栅设计优化

Design and optimization of dual-side metal grating for quantum well infrared photodetector

提出了一种增强量子阱红外探测器耦合效率的双面金属光栅结构。采用三维时域有限差分算法(3D-FDTD)对GaAs/AlGaAs量子阱红外探测器双面结构金属光栅进行了仿真分析。通过对比不同周期、占空比、金属层厚度结构参数下探测器的电场分布及相对耦合效率,确定了4.8μm探测器优化的双面金属光栅结构。与顶部和底部单层金属光栅结构比较,双面金属光栅结构探测器相对耦合效率提高到3倍以上。探测器相对耦合效率随光栅周期变化的双峰曲线特性体现了双面金属光栅结构在双色量子阱红外探测器光耦合方面的潜力。同时该结构还可以应用于单色、双色及多色量子阱焦平面红外探测器。

A new structure of dual side metal grating used to improve coupling efficiency was demonstrated. By using the three dimensional finite difference time domain algorithm, the proposed dual side metal grating for GaAs/AlGaAs Quantum Well Infrared Photodetector was studied. The optimization parameters at wavelength 4.8μm were confirmed by the electric field distribution and relative coupling efficiency at different periods, duty circles and metal thicknesses. The relative coupling efficiency of the proposed dual side metal grating was over three times of the counterparts of single side metal grating at front or back. The bimodal curve of the relative coupling efficiency for the dual side metal grating inspires possibility for potential application for two color Quantum Well Infrared Photodetector. The dual side metal grating can also be used to couple perpendicular incident light into one color, two color and multi color Quantum Well Infrared Photodetectors and offers a high coupling efficiency.