Photoconductive GaAs/AlGaAs quantum well infrared photodetector (QWIP) achieves best performance when the well has its first excited state resonant with barrier height. Optimum QWIP structure parameters can be designed according to this rule. The parameters calculated by simple square well model taking account of variable effective mass are not accurate enough and can merely provide a rough estimation for actual QWIP devices. Higher order effects including band nonparabolicity, quantum confined Stark-effect and Coulomb interaction of large number of charge carriers (also known as Many-body effect) can have considerable influence on the energy level of quantum wells. Band nonparabolicity effect was included in the calculation in this paper. And a group of optimized GaAs/AlGaAs n-type QWIP structure parameters covering wavelength from 7 μm to 16 μm were systematically calculated, using one band effective mass approximation (EMA) and shooting method. These calculated results were carefully compared with those where band nonparabolicity was not considered, and 4 ± 2% discrepancy was found. Since a photoconductive QWIP normally works under a certain bias, change of the confined state energy level and shift of peak wavelength caused by the quantum confined Stark-effect were calculated and discussed. All the calculated quantum well structure parameters in this paper will offer a more accurate guide for QWIP fabrication.

Date Published: 22 October 2010
PDF: 6 pages
Proc. SPIE 7658, 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronic Materials and Devices for Detector, Imager, Display, and Energy Conversion Technology, 76581U (22 October 2010); doi: 10.1117/12.867691

Published in SPIE Proceedings Vol. 7658:
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronic Materials and Devices for Detector, Imager, Display, and Energy Conversion Technology
Yadong Jiang; Bernard Kippelen; Junsheng Yu, Editor(s)