Experimental observation of transient photocurrent overshoot in quantum well infrared photodetectors

The experimental results on nonlinear transient photocurrent behavior in qu antum well infrared photodetectors (QWIPs) are presented. When the backgrou nd photocurrent was less than the transient photocurrent, the QWIPs with sm all number of QWs revealed a strongly nonlinear behavior. A photocurrent ov ershoot, the amplitude of which could be over 50% of the steady state photo current, in response to a high power step-like infrared illumination, was o bserved. Numerical simulations reveal that this effect is related to the ti me dependent nonlinearity of QWIP responsivity due to the redistribution of the electric field in QWIP. (C) 2001 Elsevier Science B.V. All rights rese rved.