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A photoluminescence study of self-assembled InAs/GaAs quantum dots under the influence of magnetic fields perpendicular and parallel to the dot layer is presented. At low temperatures, the magnetic field perpendicular to the dot layer alters the in-plane transport properties due to localization of carriers in wetting layer (WL) potential fluctuations. Decreased transport in the WL results in a reduced capture into the quantum dots and consequently a weakened dot-related emission. The effect of the magnetic field exhibits a considerable dot density dependence, which confirms the correlation to the in-plane transport properties. An interesting effect is observed at temperatures above approximately 100 K, for which magnetic fields, both perpendicular and parallel to the dot layer, induced an increment of the quantum dot photoluminescence. This effect is ascribed to the magnetic confinement of the exciton wave function, which increases the probability for carrier capture and localization in the dot, but affects also the radiative recombination with a reduced radiative lifetime in the dots under magnetic compression. Original Publication:Mats Larsson, Evgenii Moskalenko, Andréas Larsson, Per-Olof Holtz, C. Verdozzi, C.-O. Almbladh, W. V. Schoenfeld and P. M. Petroff, Magnetic field effects on optical and transport properties in InAs/GaAs quantum dots, 2006, Physical Review B, (74), 245312.http://dx.doi.org/10.1103/PhysRevB.74.245312Copyright: American Physical Societyhttp://www.aps.org/

A microphotoluminescence study of single InAs/GaAs quantum dots subjected to a lateral external electric field gives insight into carrier transport and capture processes into Stranski-Krastanov-grown quantum dots. The results obtained on the excitons in a single dot demonstrate a considerable luminescence intensity enhancement of the dot as well as a charge redistribution when an electric field is applied. The charge reconfiguration is evidenced by the transition from a predominantly negatively charged to a neutral charge state of the exciton. The model proposed to explain the charge redistribution is based on an effective hole localization at the potential fluctuations of the wetting layer. Original Publication:Evgenii Moskalenko, Mats Larsson, Per-Olof Holtz, W. V. Schoenfeld and P. M. Petroff, Carrier transport in self-organized InAs/GaAs quantum-dot structures studied by single-dot spectroscopy, 2006, Physical Review B, (73), 155336.http://dx.doi.org/10.1103/PhysRevB.73.155336Copyright: American Physical Societyhttp://www.aps.org/