|Title:||Single-exciton energy shell structure in InAs/GaAs quantum dots|
Cheng, S. J.
Department of Electrophysics
|Keywords:||bound states;exchange interactions (electron);excited states;excitons;gallium arsenide;III-V semiconductors;indium compounds;magneto-optical effects;photoluminescence;semiconductor quantum dots;spectral line shift|
|Abstract:||The energy shell structure of a single exciton confined in a self-assembled quantum dot (QD), including excited states, is studied in a regime where the direct Coulomb attraction energy is comparable to the kinetic energy of the carriers. This is achieved via magnetophotoluminescence excitation spectroscopy experiments, where a magnetic field applied perpendicular to the plane of the QD is used to reveal the angular-momentum content of energy shells. The absorption spectrum of the QDs is modeled, and comparison with experiment allows us to relate the observed transitions to interband QD bound-state transitions. The blueshift of the absorption peaks compared to the emission peaks is then interpreted in terms of many-body interactions, and we show that for a highly symmetric situation, the observed energy difference gives a direct measurement of the extra exchange energy gained upon addition of an extra exciton in the QD.|
|Journal:||PHYSICAL REVIEW B|
|Appears in Collections:||Articles|