Photon absorption in a semiconductor produces bright excitons that recombine very fast into photons. Here, we 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 an 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.

• Received 13 October 2019
• Revised 28 March 2020
• Accepted 1 April 2020

DOI:https://doi.org/10.1103/PhysRevB.101.161405