Observation of a single photoluminescence peak from a single quantum dot

Abstract

We observed a very sharp photoluminescence peak from a single GaAs/AlGaAs quantum dot structure by using a microphotoluminescence measurement technique. The spectral linewidth was more suppressed by decreasing the excitation laser power, which is mainly due to reduction of the filling effect of quantized energy levels. The minimal spectral linewidth with low excitation laser power was 0.9 meV.

Disorder induced broadening in multimillion atom alloyed quantum dot systems

“…4 As quantum dots of diameter 30 nm using an sp 3 d 5 s* tight binding model. It has been demonstrated that under the assumption of no alloy clustering, the disorder-induced contribution to the broadening is small (less than 0.35 meV) compared to the empirically measured total linewidth broadening and sensitive to the applied boundary conditions, so that care must be taken to ensure proper convergence.…”

“…4 As QD of diameter 30 nm and height 5.4 nm containing roughly 2 × 10 5 atoms embedded in a finite GaAs box, which is meant to approximate an infinite one. This particular model was selected for comparison with previously published experimental results [2,3].…”

“…We find that for a typical dome-shaped In 0.6 Ga 0. 4 As QD of diameter 30 nm, the broadening induced by the disorder is less than 0.35 meV.…”

“…The best photoluminescence (PL) measurements for ensembles of QDs have found linewidths on the order of 20 meV for selfassembled InGaAs QDs grown on GaAs substrates [1 -3]. Single QD measurements on AlGaAs/GaAs QDs, by contrast, can exhibit very narrow linewidths (~0.9 meV) [4]. However, even in a "perfect" ensemble in which all QDs have the same size and experience identical externally-induced strain, QDs composed of alloyed materials will still exhibit variations in linewidth that arise from differences in the spatial distribution of the constituent cations and anions.…”

InGaAs quantum dots formed in tetrahedral-shaped recesses on GaAs (111)B grown by metalorganic chemical vapor deposition

“…It has been reported that sharp luminescence from a QD can be observed under very weak excitation which creates only one electron-hole pair existing in a QD. 24,25 At higher excitation, more carriers are created in and in the vicinity of the QD, leading not only to band filling but also affecting the recombination lifetime in a QD. Since the linewidth correlates with the lifetime, we believe that this might be the cause of the spectrum broadening.…”