NONEQUILIBRIUM DIAGRAMS OF A SINGLE-QUANTUM-WELL LASER

We studied the operation of a single quantum well laser by examining t he tested device with a scanning electron microscope (SEM) working in differential voltage contrast (DVC) mode. A MOCVD-grown structure cons ists of 60 Angstrom of In0.2Ga0.8As, positioned between layers of GaAs , each 100 Angstrom thick. The specially cleaved laser structure was f orward biased to get through the inverse population, threshold, and st imulated emission mode. In various modes of operation of the laser, th e in situ DVC profiling of the quasi-Fermi energy across the device wa s performed. The intensity of the laser emission was simultaneously me asured by a detector positioned in the SEM chamber. Starting with an e quilibrium energy diagrams of an unbiased laser, we reconstructed the complete nonequilibrium energy diagrams from the experimental profile of quasi-Fermi levels. (C) 1998 Academic Press Limited.