Metal–Semiconductor-Metal Structure Enhanced Quantum Dot Infrared Photodetector for Near-Infrared

Quantum dot infrared photodetectors (QDIPs) have garnered significant interest from researchers over recent decades. The enhancement of QDIP absorption has increasingly become a focal point of investigation. Employing metal–semiconductor-metal (MSM) structures to boost absorption represents a prevailing trend in contemporary research. In this study, we introduce the MSM structure to the conventional QDIP and design a bespoke metal grating structure for it. This enhanced QDIP markedly boosts the absorptance of incident light in the near-infrared (NIR) region. Simulations using COMSOL software reveal that the conventional QDIP demonstrates an absorption peak of 46.11% at 351 THz. In contrast, the enhanced QDIP displays absorption peaks of 99.23%, 99.19%, 97.01%, and 89.23% at frequencies of 137 THz, 217 THz, 294 THz, and 367 THz, respectively. The maximum absorptance of the enhanced QDIP reaches 99.23%, which is 2.15 times greater than that of the conventional QDIP. Incorporating the MSM structure substantially enhances the absorptance of the QDIP in the near-infrared region. It is anticipated that this study will offer valuable theoretical guidance in the realm of near-infrared detection.