Energy Transfer Processes in InAs/GaAs Quantum Dot Bilayer Structure
M. Pieczarka a, A. Maryński a, P. Podemski a, J. Misiewicz a, P.D. Spencer b, R. Murray b and G. Sęk a
aLaboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
bBlackett Laboratory, Physics Department, Imperial College London, London, SW7 2AZ, United Kingdom
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We investigate double layer InAs/GaAs quantum dots grown in the Stransky-Krastanov mode by molecular beam epitaxy. The sample consists of two layers of InAs quantum dots separated by 10 nm thick GaAs layer, where the top quantum dot layer of an improved homogeneity is covered by an InGaAs cap. This configuration has allowed for the extension of the dots' emission to longer wavelengths. We probed the carrier transfer between the states confined in a double quantum well composed of InGaAs cap and the quantum dots wetting layer to the states in the quantum dots by means of photoluminescence excitation and photoreflectance spectroscopies. Efficient emission from quantum dots excited at the double quantum well ground state energy was observed. There is also presented a discussion on the carrier injection efficiency from the capping layer to the quantum dots.

DOI: 10.12693/APhysPolA.129.A-59
PACS numbers: 78.67.Hc, 71.35.-y, 78.55.-m