Exciton lifetime and spin dynamics in type-I In1-xAlxAs/Ga0.67Al0.33As quantum dots: Photoluminescence and pump-probe experiments

A. Ben Daly , Frédéric Bernardot (1) , Thierry Barisien (1) , E. Galopin , A. Lermaitre (2) , M. A. Maaref , Christophe Testelin (1)

1 INSP - Institut des Nanosciences de Paris
2 LPN - Laboratoire de photonique et de nanostructures

The exciton lifetime and spin relaxation have been studied in self-assembled In1-xAlxAs/Ga0.67Al0.33As quantum dots (QDs). Time-resolved photoluminescence and resonant pump-probe measurements were performed, at variable temperature and for different QD aluminium compositions. At low temperature, a long exciton-spin relaxation time has been measured, in agreement with the QD zero-dimensional confinement and the quenching of the relaxation mechanisms. The existence of a quasi-2D regime, in sample with a high QD density, has been observed. The importance of thermally-activated processes toward excited states is also evidenced, for QDs with different compositions and sizes. (C) 2014 Elsevier B.V. All rights reserved.

Mots clés: Quantum dots; Time-resolved photoluminescence; Pump-probe; Spin relaxation time

Domaines: Matière Condensée [cond-mat]

A. Ben Daly, Frédéric Bernardot, Thierry Barisien, E. Galopin, A. Lermaitre, et al.. Exciton lifetime and spin dynamics in type-I In1-xAlxAs/Ga0.67Al0.33As quantum dots: Photoluminescence and pump-probe experiments. Journal of Luminescence, 2015, 158, pp.136-141. ⟨10.1016/j.jlumin.2014.09.035⟩. ⟨hal-01229134⟩