DIFFERENTIAL REFLECTION DYNAMICS IN INASXP1-X INP (X-LESS-THAN-OR-EQUAL-TO-0.35) STRAINED-MULTIPLE-QUANTUM WELLS/

Using the pump-probe technique, we have observed time-resolved differe ntial reflection in LnAs(x)P(1-x)/InP (x less than or equal to 0.35) s trained-multiple-quantum wells. The experimental results show that bar rier height, interface roughness and well width influence strongly the differential reflection dynamics. For samples with the same interface quality and almost the same well width, the delay time of the differe ntial reflection decreases with increasing barrier height, while for t he sample with rough interface and narrower wells, the delay time of t he differential reflection is much slower, although it has a larger ba rrier height. To understand the experimental results, we have performe d a simulation study of temporal and spatial evolutions of photoexcite d carriers in the samples, and the influence of various physics proces ses on the photoexcited carrier dynamics has been discussed. From the calculated and the measured results, we conclude that carrier diffusio n in the cap layer and the barriers plays a dominant role in determini ng the differential reflection dynamics. (C) 1998 American Institute o f Physics.