Photocreation of a dark electron-hole pair in a quantum dot

Abstract

Photon absorption in a semiconductor produces bright excitons that recombine very fast into photons. We here show that in a quantum dot set close to a p-doped reservoir, this absorption can produce a dark duo, i.e., an electron-hole pair that does not emit light. This unexpected effect relies on the fact that the wave function for a hole leaks out of a finite-barrier dot less than for electron. This difference can render the positively charged trio unstable in the dot by tuning the applied bias voltage in a field-effect device. The unstable trio that would result from photon absorption in a positively charged dot, has to eject one of its two holes. The remaining duo can be made dark with a probability close to 100% after a few pumping cycles with linearly polarized photons, in this way engineering long-lived initial states for quantum information processing.

5 pages, 3 figures, to be published in Phys. Rev. B Rapid Comm

References in corpus (7)

• Deterministic Generation of a Cluster State of Entangled Photons
• Hole - Nuclear Spin Interaction in Quantum Dots
• Determinisitic Writing and Control of the Dark Exciton Spin using Short Single Optical Pulses
• Atomistic theory of dark excitons in self-assembled quantum dots of reduced symmetry
• In-plane radiative recombination channel of a dark exciton in self-assembled quantum dots
• Spin-orbit coupling: atom versus semiconductor crystal
• Fundamental differences between exciton and quantum dot duo