Type-I and Type-II Confinement in Quantum Dots: Excitonic Fine Structure
V. Křápeka, P. Klenovský b, T. Šikolaa,c
aCentral European Institute of Technology, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic
bCentral European Institute of Technology, Masaryk University, Kamenice 753, 625 00 Brno, Czech Republic
cInstitute of Physical Engineering, Brno University of Technology, Technická 2, 616 69 Brno, Czech Republic
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We have theoretically studied type-I and type-II confinement in InAs quantum dots with GaAs1-ySby capping layer. The character of the confinement can be adjusted by the Sb content. We have found that upon the transition from type-I to type-II confinement the hole wave functions change the topology from a compact shape to a two-segment shape, resulting in the complex changes in the exciton fine structure splitting with zero values at particular compositions. Additionally, a high exciton radiative recombination probability is preserved even in type-II. This allows to design strongly luminescent quantum dots with naturally low fine structure splitting, which could serve as sources of entangled photon pairs for quantum communication.

DOI: 10.12693/APhysPolA.129.A-66
PACS numbers: 71.35.-y, 73.21.La, 81.05.Ea