Observation of negatively charged excitons and excited states of multi-excitons in quantum dots embedded in modulation doping structures

Existence of negatively charged excitons in quantum dots (QDs) is confirmed by the measurement of the bias dependence of luminescence from modulation doped structures with embedded QDs. Excited states of multi-particle states are also identified from the bias as well as the excitation intensity dependence of micro-photoluminescence peaks.