TITLE:
Excitation Transfer in Vertically Stacked in (Ga)As/GaAs Quantum Rings
AUTHORS:
R. Naouari, W. Ouerghui, J. Martinez-Pastor, J. Gomis, M. A. Maaref, D. Granados, J. M. Garcia
KEYWORDS:
Quantum Rings; Vertical Stack; Time Resolved Photoluminescence
JOURNAL NAME:
Journal of Modern Physics,
Vol.3 No.6,
June
21,
2012
ABSTRACT: Carrier tunnelling through GaAs barriers of different thicknesses is investigated in vertically InGaAs/GaAs quantum rings (QR’s). Shorter PL decay time of the ground state emission of high-energy component in the sample with thicker spacer (1.5 nm) is ascribed to both tunnelling effect between the two QR families and vertical coupling between layers in the stacks. We found that tunnelling time between QR’s followed the Wentzel-Kramers-Brillouin (WKB) approximation. The non resonant tunnelling rate between QR’s is found to be different by one order of magnitude from the rate in quantum dots (QD’s).