Broadband absorption enhancement for InAsSb-based mid-infrared photodetectors

• Main Author: Wang, Weilin
• Other Authors: ZHANG Dao Hua
• Format: Thesis-Master by Coursework
• Language: English
• Published: Nanyang Technological University 2020
• Subjects: Engineering::Electrical and electronic engineering::Optics, optoelectronics, photonics
• Online Access: https://hdl.handle.net/10356/141150
• Institution: Nanyang Technological University

In modern detector technologies, antimony (Sb)-based photodetectors have shown great significances on the middle wavelength infrared (MWIR) spectra due to its various advantages in obtaining good detection performance. In this dissertation, the hetero InAsSb nip photodiode is designed as the basic MWIR detector, where the large bandgap layers are introduced between absorption layer and contact layers to decrease noise current. To further increase the light absorption without sacrificing the response speed, four types of photon-trapping structures are designed and modeled in Finite Difference Time Domain (FDTD) simulation software. By simulating the reflection and absorption of devices w/o photon-trapping structure, significant reflection reduction is observed, and a relative absorption improvement of about 40% is reached for photon-trapping devices in the mid-wavelength region between 2 and 5 μm. The electric field distribution is also generated to demonstrate the lateral-mode effect on enhancing the absorption.