Absorption and quantum efficiency of GeSn nanopillar arrays for infrared detectors

Abstract

This research investigates the optical absorption and quantum efficiency of germanium-tin (GeSn) materials with a tin(Sn) content of 4.5%, and their potential applications in infrared optoelectronic systems. It has two forms which are crystalline(c-GeSn) and amorphous(a-GeSn) states. The finite-difference time-domain (FDTD) method was used to simulate the absorption of c-GeSn and a-GeSn. By optimising the period, radius and height of the nanopillars, the optimal parameters were determined, and it was found that the c-GeSn nanopillars in that case had a very stable and excellent absorption in the near-infrared (NIR) band. Calculated by MATLAB that the cylindrical nanopillars could reach a maximum quantum efficiency of 3.67% at 1350 nm. It is anticipated that this study will contribute to the further understanding of GeSn and provide a theoretical basis for designing high-performance infrared photodetectors.