OPTICAL-PROPERTIES OF GAAS ALXGA1-XAS QUANTUM-WELLS DISORDERED BY ION-IMPLANTATION/

Photoluminescence, photoluminescence excitation, and time-resolved opt ical spectroscopy are used to study ion-induced disordered GaAs/AlxGa1 -xAs quantum wells. The experimental data are used to quantify the str uctural modifications of the implanted quantum wells after they are th ermally annealed. We show that a finite density of nonradiative traps, associated with the Al atoms which diffused into the GaAs quantum wel l during the annealing process, is responsible for the quantum wells' photoluminescence quenching. We use a simple vacancy controlled diffus ion mechanism to model the ion-induced structural modification and its dose dependence. Our model explains the ratio between the interface d iffusion length (similar to 10 Angstrom and the lateral extent of the intermixing around each traversing ion track (similar to 200 Angstrom) . It fails, however, to predict the correct dependence of the interfac e diffusion length on the implantation dose.