The nonlinear optical and transport properties of a nipi-doped h-&a, -,As/GaAs multiple-quantum well sample (s=O.23) has been studied using a novel approach called electron-beam-induced absorption modulation IERIA). The absorption in the sample is modulated as a result of screening of the built-in eiectric field in the nipi structure due to excess carrier generation. The change in field causes a Stark shift of the first quantized optical transitions in QWs which are situated in the intrinsic

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... ers. ln ERL4, a scanning electron probe is used to locally generate an electron-hole plasma that is used to study the spatial distribution of defects that impede excess carrier transport and reduce the lifetime of spatially separated carriers. The Stark shift in the h$QW structure is imaged with micrometer-scale resolution and is compared with cathodoluminescence imaging results which slow dark line defects resulting from strain-induced misfit dislocations. Theoretical calculations using Airy functions in the transfer-matrix method with a self-consistent field approximation were used to determine the energy states, wave functions, and carrier recombination lifetimes of the MQW as a function of the built-in field. A quantitative phenomenological analysis is employed to determine the built-in field, excess carrier lifetime, and ambipohr diffusion coefficient as a function of the excitation de.nsity. The defects are found to create potential barriers and recombination centers which impede transport and markedly reduce the excess carrier lifetime. 6 I995 American institute of Physics.