High-speed quantum well infrared photodetctor based on intersubband transitions

Abstract

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.