High-speed quantum well infrared photodetctor based on intersubband transitions

• Main Author: WU, Yujin
• Other Authors: Wang Qijie
• Format: Thesis-Master by Coursework
• Language: English
• Published: Nanyang Technological University 2024
• Subjects: Engineering; Physics
• Online Access: https://hdl.handle.net/10356/178225
• Institution: Nanyang Technological University

The development of infrared (IR) detection technology has evolved significantly over the decades. Quantum Well Infrared Photodetectors (QWIPs) have emerged as a breakthrough in this field, leveraging intersubband transitions to achieve infrared photon absorption and electron transitions through quantum mechani- cal effects. This dissertation focuses on the fabrication and characterization of high-speed QWIPs based on intersubband transitions, with the aim of enhancing their response speed and detection efficiency. The research outlines a reliable method for fabricating QWIPs, involving epitaxial growth, active region defini- tion, mesa isolation, dielectric deposition, gold deposition, and polishing. The fabricated QWIPs were tested for their I-V characteristics, optical response, and high-speed behavior. Results demonstrated significant improvements in response speed, with a 3 dB cutoff frequency around 250 MHz at room temperature and up to 1.1 GHz under cryogenic conditions. These findings suggest that the developed high-speed QWIPs can be effectively integrated into commercial systems, thereby broadening the practical applications of infrared detection.