Photocarrier transport and recombination in an asymmetric quantum well subjected to a focused excitation

Electron and hole transport in an InGaAs/InP asymmetric quantum well are in vestigated by surface scanning the microluminescence signal from the quantu m well recombination. Under illumination by a tightly focused laser beam, w e show that a novel in-plane hole diffusion process occurs in the quantum w ell, to which we associate an effective hole lifetime. This effective lifet ime is dependent upon the electron accumulation, a result expected to allow an alternative estimate of the two-dimensional (2D) electron density. Vert ical and in-plane transport and recombination processes are additionally in vestigated in connection with observed temperature-dependent saturation of the luminescence intensity. (C) 2001 Elsevier Science Ltd. All rights reser ved.