Temperature effects on the radiative recombination in InAlAs/GaAlAs quantum dots

• Published in: Solid state communications 2016-02, Vol.227, p.9-12
• Main Authors: Ben Daly, A., Bernardot, F., Barisien, T., Lemaître, A., Maaref, M.A., Testelin, C.
• Format: Article
• Language: English
• Subjects: Carrier lifetime; Photoluminescence; Physics; Quantum dots; Time-resolved photoluminescence
• ISSN: 0038-1098; 1879-2766
• DOI: 10.1016/j.ssc.2015.11.011

The influence of the temperature has been studied in self-assembled InAlAs/GaAlAs quantum dots (QDs) using photoluminescence (PL) and time-resolved PL (TRPL). With increasing temperature, the exciton retrapping in QDs, after a thermal activation, is evidenced and confirmed by a narrowing of the PL spectrum width, and an increase of the PL decay time. From the temperature dependence of the integrate PL signal, the activation energy is estimated at 110meV, in agreement with the electronic state in QD and wetting layer (WL) determinate by PL spectroscopy measurements. The influence of the QD size on the QD confinement energy, is also observed in the evolution of the decay time with temperature and detection energy. •Photoluminescence (PL) and time-resolved photoluminescence (TRPL) studies have been performed on a visible-emitting InAlAs/GaAlAs quantum dot (QD) sample.•The observed decay times increase at low temperature up to a critical temperature which increases with decreasing emission energy, then decrease steeply with increasing temperatures.•This temperature dependence of the PL decays is attributed to thermal activation of excitons from the QDs to the wetting layer and to exciton retrapping.•Signatures of this thermally activated process are also evidenced in FWHM and integrate PL dependence on temperature.