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Strain-induced localized states within the matrix continuum of self-assembled quantum dots

2009; American Institute of Physics; Volume: 95; Issue: 2 Linguagem: Inglês

10.1063/1.3159875

1520-8842

Voicu Popescu, Gabriel Bester, Alex Zunger,

Quantum and electron transport phenomena

Quantum dot-based infrared detectors often involve transitions from confined states of the dot to states above the minimum of the conduction band continuum of the matrix. We discuss the existence of two types of resonant states within this continuum in self-assembled dots: (i) virtual bound states, which characterize square wells even without strain and (ii) strain-induced localized states. The latter emerge due to the appearance of “potential wings” near the dot, related to the curvature of the dots. While states (i) do couple to the continuum, states (ii) are sheltered by the wings, giving rise to sharp absorption peaks.