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

Journal Article · Mon Jul 28 00:00:00 EDT 2014 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4891828· OSTI ID:22311181

Tang, Jing ^[1]; Cao, Shuo; Gao, Yunan; Sun, Yue; Jin, Kuijuan; Xu, Xiulai ^[2]; Geng, Weidong ^[1]; Williams, David A. ^[3]

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1. Institute of Photo-electronic Thin Film Devices and Technology, Nankai University, Tianjin 300071 (China)
2. Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)
3. Hitachi Cambridge Laboratory, Cavendish Laboratory, Cambridge CB3 0HE (United Kingdom)

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.

• OSTI ID: 22311181
• Journal Information: Applied Physics Letters, Vol. 105, Issue 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CAPTURE
CARRIERS
CHARGE STATES
CRYSTAL GROWTH
EFFECTIVE MASS
ELECTRIC FIELDS
ELECTRIC POTENTIAL
ELECTRON DRIFT
ELECTRONS
EXCITONS
GALLIUM ARSENIDES
INDIUM ARSENIDES
INTERFACES
LAYERS
MAGNETIC FIELDS
PHOTOLUMINESCENCE
QUANTUM DOTS
SPECTROSCOPY
TRAPPING
TUNNEL EFFECT