Radiative lifetimes in undoped andp-doped InAs/GaAs quantum dots

The effect of high-In content capping layers on low-density bimodal-sized InAs quantum dots

“…A similar dependence has been found in Ref. 44 for InAs/GaAs QDs grown in p-doped samples; in this case, the behavior was attributed to holes escaping from charged QDs. In our case, since both QD1 and QD2 families exhibit this behavior, we can conclude that it does not depend on peculiar features of QDs but it should rather depend on the characteristics of the high In content UCL.…”

“…28 The observed increase in s d in the mid-T range is characterized by an activation energy between 20 and 80 meV, as 194306 (2013) in other similar nanostructures, 41,42 InAs/GaAs selfassembled QDs 43,44 and quantum ring nanostructures. 45,46 The origin of this behavior has been attributed to a thermally induced population of dark excitons; 44,45 where transitions p e -s e (or p h -s h ), initially forbidden, becomes allowed due to thermal transfer. 47 Comparing the Arrhenius plots for PL intensity and s d in each sample, one can observe that the main PL quenching mechanism starts at the same mid-T range and very close activation energies are deduced for each UCL composition.…”

“…Given that the PL decay time contains radiative and non radiative contributions 44 1 where s R corresponds to the radiative time, approximately equal to the measured value s d (13 K), and s NR to the nonradiative time (mainly determined by the thermionic emission of carriers towards the WL)…”

Competitive carrier interactions influencing the emission dynamics of GaAsSb-capped InAs quantum dots

“…This value is consistent with the decay times measured at low temperature for conventional InAs/ GaAs QDs. 17 A different behaviour is observed for the two ESs, where the carrier lifetimes measured at the shortwavelength side of each peak are much shorter than those measured at the long-wavelength side. Such strong wavelength-dependent emission dynamics represents, together with the red-shift of the peak position with decreasing excitation powers, another characteristic of type-II band aligned heterostructures.…”

Resolving Zeeman splitting in quantum dot ensembles

“…For this work undoped and p-doped (at a doping level of 3 holes/QD) samples were chosen to highlight the applicability of the technique. Further structure and growth details of the ensembles used may be found in Harbord et al 5 All experiments were performed with the samples maintained at 8 K in a magneto-cryostat, capable of applying up to 5 T to the QD sample in the Faraday geometry. Unpolarized optical excitation was provided by a Helium-Neon laser at an excitation wavelength of 632.8 nm.…”