Abstract
Temperature-dependent photoluminescence (PL) and the corresponding carrier dynamics of standard and coupled type-II GaSb/GaAs quantum rings (QRs) are investigated in this article. Compared with standard QRs, the slower PL intensity decay of coupled QRs with increasing temperature is attributed to the depression of thermal quenching. More intense PL intensity is also observed for the coupled-QR sample at room temperature. With further reducing the GaAs spacer layer thickness to 2 nm, near two-times PL enhancement is observed. The results indicate that with the enhanced luminescence intensity of coupled-QR structure, type-II nano-structures may be utilized for light-emitting device applications. © 2013 Elsevier B.V. All rights reserved.