Space charge buildup in quantum-well infrared photodetectors (QWIP's) is shown to be the main reason for the low-power nonlinear photoresponse of the QWIP's. We present a model that takes into account the space charge distribution across the quantum wells and derive a simple expression for the intensity dependent responsivity of the QWIP. A comparison of our model with a set of intensity dependent responsivity measurements performed on a 50-period QWIP shows a very good agreement with our model as long as the QWIP is far from saturation.
Bibliographical noteFunding Information:
Manuscript received May 8, 1998; revised June 22, 1998. The work of A. Sa’ar and C. Mermelstein was supported by the Israeli Ministry of Science under Grant 5856. The work of H. Schneider, C. Schoenbein, and M. Walther was supported by the Bundesministerium fuer Verteidigung.
- Nonlinear photoresponse
- Quantum-well infrared photodetectors (QWIPs)
- Semiconductor infrared detetors