Electrical control of optically pumped electron spin in a single GaAs/AlAs quantum dot fabricated by nanohole infilling
We demonstrate here electrical control of the sign of the circularly polarized emission from the negatively charged trion, going from co- to contrapolarized with respect to the circular polarization of the laser, using a GaAs/AlAs quantum dot (QD) embedded in a field effect structure. The voltage ra...
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Veröffentlicht in: | Physical review. B 2020-07, Vol.102 (3), p.1, Article 035406 |
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Sprache: | eng |
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Zusammenfassung: | We demonstrate here electrical control of the sign of the circularly polarized emission from the negatively charged trion, going from co- to contrapolarized with respect to the circular polarization of the laser, using a GaAs/AlAs quantum dot (QD) embedded in a field effect structure. The voltage range over which the trion is negatively (contra) circularly polarized is shown to be dependent on the laser excitation energy within the P -shell resonance. The negative polarization never exceeds ∼ − 15 % , in stark contrast to measurements on InAs/GaAs QDs reported by M. E. Ware et al. [Phys. Rev. Lett. 95, 177403 (2005).] in which a negative polarization reaching − 95 % was observed. This result is shown to be a consequence of the low-symmetry confinement potential of these GaAs/AlAs QD, which are fabricated by partial infilling of asymmetric droplet-etched nanoholes. This low QD symmetry also leads to optical activity of the dark spin configuration of the triplet state, which we measure experimentally by photoluminescence excitation spectroscopy. A simple, semiquantitative model explaining both the optical activity of the dark spin configuration and the maximum degree of negative polarization is presented. |
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ISSN: | 2469-9950 0163-1829 2469-9969 1095-3795 |
DOI: | 10.1103/PhysRevB.102.035406 |