Charge state control in single InAs/GaAs quantum dots by external electric and magnetic fields

Abstract

We report a photoluminescence (PL) spectroscopy study of charge state control in single self-assembled InAs/GaAs quantum dots by applying electric and/or magnetic fields at 4.2 K. Neutral and charged exciton complexes were observed under applied bias voltages from -0.5 V to 0.5 V by controlling the carrier tunneling. The highly negatively charged exciton emission becomes stronger with increasing pumping power, arising from the fact that electrons have a smaller effective mass than holes and are more easily captured by the quantum dots. The integrated PL intensity of negatively charged excitons is affected significantly by a magnetic field applied along the sample growth axis. This observation is explained by a reduction in the electron drift velocity caused by an applied magnetic field, which increases the probability of non-resonantly excited electrons being trapped by localized potentials at the wetting layer interface, and results in fewer electrons distributed in the quantum dots. The hole drift velocity is also affected by the magnetic field, but it is much weaker.

14 pages, 4 figures

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Cited by in corpus (6)

• Probing the dark exciton states of a single quantum dot using photocurrent spectroscopy in magnetic fields
• Observation of coupling between zero- and two-dimensional semiconductor systems based on anomalous diamagnetic effects
• Longitudinal wave function control in single quantum dots with an applied magnetic field
• Anisotropies of the g-factor tensor and diamagnetic coefficient in crystal-phase quantum dots in InP nanowires
• Tuning the carrier tunneling in a single quantum dot with a magnetic field in Faraday geometry
• Fundamental intrinsic lifetimes in semiconductor self-assembled quantum dots