Nonlinear photoresponse effects at high excitation power in quantum well infrared photodetectors (QWIPs) are studied both experimentally and theoretically. The photoconductivity nonlinearity is mainly caused by a redistribution of the electric potential at high power, which leads to a decrease of electric field in the bulk of the QWIP. As a result of the decreased field, the photoexcited electron escape probability and drift velocity decrease, resulting in a decrease of responsivity. These effects are strongly influenced by QWIP structural parameters and operating conditions. In QWIPs with a few QWs the IR power required to observe a decrease of responsivity is much lower than that needed to cause the saturation of the intersubband absorption. Key factors in designing a QWIP with a suppressed nonlinearity are discussed.

Date Published: 15 April 1997
PDF: 8 pages
Proc. SPIE 2999, Photodetectors: Materials and Devices II, (15 April 1997); doi: 10.1117/12.271210

Published in SPIE Proceedings Vol. 2999:
Photodetectors: Materials and Devices II
Gail J. Brown; Manijeh Razeghi, Editor(s)