Design and simulation of metasurfaces for enhancing mid-infared photodetection

Nowadays, middle wavelength infrared (MWIR, 3–5 m) photodetectors have been applied in a variety of areas, such as communication, security, remote sensing, and medical diagnostics. However, most of MWIR photodetectors can only work under low temperature with a limited sensitivity for the light due to material property. At the same time, surface plasmon polaritons (SPPs) have a rapid development and attracted wide attention as they can enhance the interaction of light with matter remarkably. The photocurrent in the photodetector can be enhanced significantly by confining the light to a very small volume and promoting absorption of intense light. Thus, they can improve the detection performance owing to their strong capability of localizing electromagnetic waves in the deep subwavelength scale. In this dissertation, we used plasmonic enhancement strategy to improve the sensitivity without sacrificing the response speed. We designed several novel metallic patch structures for promoting the performance of InAs0.91Sb0.09-based heterojunction p-i-n photodiode. The corresponding simulation results using the FDTD software show that using square-shaped Al or Au patch structures excites the obvious resonance in MWIR range. Thus, they can enhance the electrical field significantly, thus leading to a better detection performance. The characteristic makes it possible for the MWIR detector to operate well under room temperature.Master of Science (Electronics