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Near-field light emission from dark-states inverted exciton occupations

G. Pistone·S. Savasta·O. Di Stefano·G. Martino·R. Girlanda·S. Portolan
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Abstract

We theoretically analyze the carrier capture and distribution among the available energy levels of a symmetric semiconductor quantum dot under continuous-wave excitation resonant with the barrier energy levels. At low temperature all the dot level-occupations but one decrease monotonically with energy. The uncovered exception, corresponding to the second (dark) energy level, displays a steady-state carrier density exceeding that of the lowest level more than a factor two. The root cause is not radiative recombination before relaxation to lower energy levels, but at the opposite, carrier trapping due to the symmetry-induced suppression of radiative recombination. Such a behaviour can be observed by collection-mode near-field optical microscopy.

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G. Pistone, S. Savasta, O. Di Stefano, G. Martino, R. Girlanda, S. Portolan. 2006-11-13. Near-field light emission from dark-states inverted exciton occupations. https://arxiv.org/abs/cond-mat/0611335

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