The effect of structural parameters on the in-plane coupling between quantum dashes of a dense ensemble in the InAs-InP material system

Abstract

In this work, we investigate the importance of lateral electronic coupling in a dense ensemble of anisotropic epitaxial nanostructures called quantum dashes. The respective confined state energy levels and the related tunneling times between two neighboring nanostructures are calculated using a simplified approach with parabolic effective masses in a single band k·p approximation, and assuming infinite size of the quantum dashes in the elongation direction. There has been studied the influence of the cross-sectional dimensions of the dashes, their lateral separation and the barrier material. Eventually, the impact of the inhomogeneity within the ensemble of nanostructures has been discussed. For the presented calculations the InAs dashes on InP substrate have been chosen as a model system because of the high areal density and strong in-plane anisotropy obtained typically in the self-assembled growth by molecular beam epitaxy.

Confinement regime in self-assembled InAs/InAlGaAs/InP quantum dashes determined from exciton and biexciton recombination kinetics

“…In general, due to the high planar density of dashes, tunneling effects between the neighboring objects would seem to be feasible. However, we have found that the quantummechanical coupling can be neglected in case of strongly inhomogeneous ensemble of QDashes, 31 which is the case for the self-assembled InAs/InP system considered here.…”

Abnormal photoluminescence properties of InAs/InAsSb in-plane ultrahigh-density quantum dots

“…4,5) According to the previous reports, 6,7) the electronic state in strongly coupled QDs became delocalized as the interdot spacing is less than about 10 nm. While there have been reports on theoretical studies regarding in-plane strong coupling between adjacent QDs, 8,9) there are fewer experimental studies on self-assembled QDs due to low QD density and large inhomogeneous broadening of the QD size. Recently, we successfully fabricated in-plane ultrahigh density (UHD) QDs of InAs/InAsSb grown epitaxially on GaAs substrates by using MBE.…”

Excited states of neutral and charged excitons in single strongly asymmetric InP-based nanostructures emitting in the telecom C band

“…Out of the abundance of semiconductor nanostructures, those prepared via molecular beam epitaxy (MBE) in InAs on InPsubstrate systems [1], especially InAs/AlGaInAs considered here [2], typically stand out with high areal density and in-plane elongation so high that it is disputable whether they should be classified as quantum dots (QDs) or quantum wires [3][4][5][6]. This fundamental ambiguity did not prevent the intense research on the properties of such objects.…”