Exciton complexes inInxGa1−xAs/<

Effects of few-particle interaction on the atomiclike levels of a single strain-induced quantum dot

“…Moreover, the biexciton binding energy found here ͑1.5 meV͒ is consistent with the calculations reported in Ref. 17 for QDs fabricated by lithography and etching starting from a In 0.14 Ga 0.86 As/GaAs quantum well. In our case the lateral geometrical extention of the QD is similar but the starting quantum well has an In content of 0.08 and a width of 8 nm resulting in a sligthly smaller exciton and biexciton binding energies.…”

“…At low photoexcitation power, the full width at half maximum of the observed lines is now reduced to 0.8 meV. Even though such a linewidth is comparable to the spectral resolution of the experiment and is limited by the sample temperature ͑about 25 K͒, we believe that the relatively large linewidth is typical of single QD structures fabricated starting from an InGaAs quantum well, 17 where photoexcited surface charges or near surface impurity states can generate fluctuation of the QD potential in time. 17,11 Moreover microscopic interface defects and In fluctuation in the original QW can contribute to the single QD line broadening.…”

“…Even though such a linewidth is comparable to the spectral resolution of the experiment and is limited by the sample temperature ͑about 25 K͒, we believe that the relatively large linewidth is typical of single QD structures fabricated starting from an InGaAs quantum well, 17 where photoexcited surface charges or near surface impurity states can generate fluctuation of the QD potential in time. 17,11 Moreover microscopic interface defects and In fluctuation in the original QW can contribute to the single QD line broadening. 18 In our case, the ground level wave function probes small compositional fluctuations in the ternary alloy well underneath the InP dot, where surface charges can eventually accumulate and affect the dots buried under the stressor.…”

“…This is not the case in dots that are isolated through a metallic mask, 16 where the Schottky barrier may change the band alignment, or in free-standing dots that are affected by charges at the surface. 17 In Fig. 1͑a͒ we show the space-integrated PL spectra of the original unprocessed sample, containing a large population of dots, as a function of the excitation intensity.…”

Influence of Optical Phonons on Optical Transitions in Semiconductor Quantum Dots

“…This result is in agreement with the experimental data obtained for the same cylindrical shape of QD but with other compounds, InAs/InP (Chauvin et. al., 2006)), As/GaAs Ga In 0.86 0.14 (Bayer et. al., 1998) or with theoretical results obtained for GaAs.…”