We have investigated the micro photoluminescence (micro-PL) spectra of a single GaAs/AlGaAs quantum dot (QD) grown on a (411)A GaAs substrate, and observed sharp luminescence lines. These luminescence lines are classified into three types in terms of their excitation-power dependence. For one of them the intensity increases linearly with excitation power density, and the others that appear at the lower and higher energy sides of the linear one exhibit superlinear dependence. The difference in the excitation-power dependence reflects the number of excitons created in a QD, namely, the linear dependence originates from the lowest state of a confined exciton, and the others from biexcitonic and multiple exciton states.
|Number of pages
|Physica Status Solidi (B): Basic Research
|Published - 2001 Mar