Correlations between optical properties and Voronoi-cell area of quantum dots

Abstract

A semiconductor quantum dot (QD) can generate highly indistinguishable single-photons at a high rate. For application in quantum communication and integration in hybrid systems, control of the QD optical properties is essential. Understanding the connection between the optical properties of a QD and the growth process is therefore important. Here, we show for GaAs QDs, grown by infilling droplet-etched nano-holes, that the emission wavelength, the neutral-to-charged exciton splitting, and the diamagnetic shift are strongly correlated with the capture zone-area, an important concept from nucleation theory. We show that the capture-zone model applies to the growth of this system even in the limit of a low QD-density in which atoms diffuse over µm-distances. The strong correlations between the various QD parameters facilitate preselection of QDs for applications with specific requirements on the QD properties; they also suggest that a spectrally narrowed QD distribution will result if QD growth on a regular lattice can be achieved. arXiv:1902.10145v3 [cond-mat.mes-hall]

Low-noise GaAs quantum dots for quantum photonics

“…All doped layers in AlGaAs have low Al-concentration (<20%). The quantum dots are surrounded by AlGaAs with higher Al-concentration (33%), to enable the growth of QDs close to rubidium-frequencies and with small fine-structure splittings 8,11 . We fabricate separate Ohmic contacts to the n + and p ++ layers.…”

“…The reason is probably the following: the GaAs QDs in our sample are grown by infilling nano-holes droplet-etched into a 10 nm-thin layer of Al 0.33 Ga 0.67 As (see Table 1). The depths of the nano-holes, and therefore the heights of the QDs, typically range from 5 nm to 10 nm 8,11 . A QD emitting at higher wavelength tends to have a larger height 11 .…”

“…The depths of the nano-holes, and therefore the heights of the QDs, typically range from 5 nm to 10 nm 8,11 . A QD emitting at higher wavelength tends to have a larger height 11 . When the height of a QD comes close to 10 nm, the optical properties could be affected by the Al 0.33 Ga 0.67 As/ Al 0.15 Ga 0.85 As interface.…”

“…GaAs QDs in an AlGaAs matrix can be self-assembled by local droplet etching 8,9 and have a spectrally narrow ensemble 10,11 . They emit at wavelengths between 700 and 800 nm.…”

Charge Tunable GaAs Quantum Dots in a Photonic n-i-p Diode

“…(c) GaAs is deposited and fills the nanohole. Nearby material diffuses into the hole, and the diffusion area (Voronoi-cell) correlates with the filling level [29]. In between the nanoholes, GaAs forms a quantum well, which is called a wetting layer, in accordance with the term used for InGaAs QDs.…”