Absorptive characteristics of GaInAsSb tip-wedge nanopillar arrays structure for infrared detector

Abstract

GaInAsSb has important application value in the field of infrared optoelectronics. In this paper, the optical properties of Ga0.84In0.16As0.14Sb0.86 nanopillar array with different tip-wedge structures are studied by using the method of finite-difference time-domain (FDTD). The simulation results show that a single tip-wedge structure cannot achieve the enhanced absorption with absorptance of more than 90 %, while the tip-wedge combination structure can effectively improve the absorptance of the nanostructure, and the absorptance of nanostructures reaches more than 97 % when the cone to column height ratio is 0.47 and the period is 500 nm. In addition, the double-cone structure can also effectively improve the absorption characteristics of the nanostructures. When the tip-wedge nanostructures have a high duty cycle, the absorption rate of the array structure can reach 93 %, which provides a theoretical basis for the preparation of high-density optical devices and reducing the difficulty of the preparation process.