Time-resolved optical characterization of InAs/InGaAs quantum dots emitting at 1.3 μm

Abstract

We present the time-resolved optical characterization of InAs/InGaAs self-assembled quantum dots emitting at 1.3 μm at room temperature. The photoluminescence decay time varies from 1.2 (5 K) to 1.8 ns (293 K). Evidence of thermalization among dots is seen in both continuous-wave and time-resolved spectra around 150 K. A short rise time of 10±2 ps is measured, indicating a fast capture and relaxation of carriers inside the dots.

Recombination kinetics of InAs quantum dots: Role of thermalization in dark states

“…In fact contradictory statements from very similar experimental results have been reported in the literature. The increase of the photoluminescence ͑PL͒ lifetime of the fundamental optical transition in QD's with increasing temperature has been equally attributed to dark states, [11][12][13] to carrier transfer between QD's, 14 to carrier escape and recapture, 15 and to reduction of the nonradiative recombination rate. 16 Clearly a supplement of analysis on this relevant point is needed.…”

Long luminescence lifetime in self-assembled InGaAs/GaAs quantum dots at room temperature

“…Note that a decrease in the PL decay time at 300 K has been widely reported in the literature. [9][10][11][12][21][22][23] The observation of long PL decay times, even at 300 K, indicates a high quality of our QD sample. The two AlAs layers can suppress the influence of nonradiative centers on the surface and in the substrate.…”

Exciton Dynamics in High Density Quantum Dot Ensembles

“…However, the temperature dependence of the PL decay time in the d=20 nm sample is different from that in the d=40 nm sample. The increase in the PL decay time with the temperature is generally explained by the thermal dissociation of excitons into the electron-hole pairs, in which the excitons escape from the QDs into the spacer layer and/or the upper subband levels of electron and holes via thermionic emission (Wang et al, 1994;Yu et al, 1996;Fiore et al, 2000;Hostein et al, 2008), which is described as lateral coupling model. We considered that the temperature dependence of the PL decay time in the d=40 nm sample can be explained by this lateral coupling model.…”