Enhanced quantum-well photoluminescence in InGaAs/InGaAsP heterostructuresfollowing excimer-laser-assisted surface processing

The influence of excimer-laser-assisted surface processing on quantum-well photoluminescence (QW FL) has been investigated in InGaAs/InGaAsP heterostr uctures capped with a thin layer of In0.53Ga0.47As. The PL mapping measurem ents carried out on samples before they were processed in a rapid thermal a nnealer indicated no significant differences in the QW PL signal intensity measured at the excimer-laser-processed sites and in their vicinity. Howeve r, a large difference in the QW PL signal, with its intensity significantly enhanced at the laser-processed sites, was observed after 10 s of rapid th ermal annealing (RTA) at 750 degrees C. The largest contrast in the PL sign al (an intensity difference up to about 100%) was obtained for a site proce ssed with 50 pulses and a laser fluence of 123 mJ/cm(2). The changes in the QW PL signal intensity have been found to coincide with the changes in the surface chemical composition that were detected with Auger electron spectr oscopy. The main difference concerns the development of a GaOx layer on the laser-processed In0.53Ga0.47As surface.