Blueshifts of the emission energy in type-II quantum dot and quantum ring nanostructures

Hodgson, P. D. and Young, R. J. and Kamarudin, M. Ahmad and Carrington, P. J. and Krier, A. and Zhuang, Q. D. and Smakman, E. P. and Koenraad, P. M. and Hayne, M. (2013) Blueshifts of the emission energy in type-II quantum dot and quantum ring nanostructures. Journal of Applied Physics, 114 (7). ISSN 0021-8979

Full text not available from this repository.

Abstract

We have studied the ensemble photoluminescence (PL) of 11 GaSb/GaAs quantum dot/ring (QD/QR) samples over >= 5 orders of magnitude of laser power. All samples exhibit a blueshift of PL energy, Delta E, with increasing excitation power, as expected for type-II structures. It is often assumed that this blueshift is due to band-bending at the type-II interface. However, for a sample where charge-state sub-peaks are observed within the PL emission, it is unequivocally shown that the blueshift due to capacitive charging is an order of magnitude larger than the band bending contribution. Moreover, the size of the blueshift and its linear dependence on occupancy predicted by a simple capacitive model are faithfully replicated in the data. In contrast, when QD/QR emission intensity, I, is used to infer QD/QR occupancy, n, via the bimolecular recombination approximation (I alpha n(2)), exponents, x, in Delta E alpha I-x are consistently lower than expected, and strongly sample dependent. We conclude that the exponent x cannot be used to differentiate between capacitive charging and band bending as the origin of the blueshift in type-II QD/QRs, because the bimolecular recombination is not applicable to type-II QD/QRs. (C) 2013 AIP Publishing LLC.

Item Type:
Journal Article
Journal or Publication Title:
Journal of Applied Physics
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/3100
Subjects:
ID Code:
67006
Deposited By:
Deposited On:
07 Oct 2013 23:03
Refereed?:
Yes
Published?:
Published
Last Modified:
28 Mar 2020 03:22