Low density InAs quantum dots grown on GaAs nanoholes

Abstract

A growth technique combining droplet epitaxy and molecular beam epitaxy (MBE) is developed to obtain a low density of InAs quantum dots (QDs) on GaAs nanoholes. This growth technique is simple, flexible, and does not require additional substrate processing. It makes possible separate control of the QD density via droplet epitaxy and the QD quality via MBE growth. In this letter the authors report the use of this technique to produce InAs QDs with a low density of 2.7×108cm−2 as well as good photoluminescence properties. The resulting samples are suitable for single QD device fabrication and applications.

Holed nanostructures formed by aluminum droplets on a GaAs substrate

“…2(d). In this diagram, we assume the initial Al droplet has the same behavior as a gallium or indium droplet in that the initial sizes and shapes of the holed nanostructures directly correspond to the initial sizes of the droplets [11,21,22,25] with the following results: (1) the inner ring diameter is the same magnitude as the diameter of the initial droplet; (2) the central hole depth is the same magnitude as the height of the initial droplet; (3) the inner ring height is ~6 nm while the outer ring height is reduced to half this value; (4) the distance between the inner and outer rings is 200 nm ± 20 nm. It should be noted that the large flat spacing between Al concentric double rings observed in this work is one distinguishing feature from the ordinary compact concentric double rings or multiple concentric nanorings observed for Ga droplet epitaxy [17].…”

“…The holed nanostructures, first demonstrated by Wang et al [21], are particularly promising candidates for the formation of uniform and low-density quantum rings [22][23][24]. However, all the previously published work has involved the formation of nanostructures from gallium (Ga) or indium (In) droplets [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24], and there has been no report of aluminum (Al) droplets on GaAs substrates, although there have been a few of papers involving Al droplets [11,25]. Investigation of the nanostructures formed from Al droplets will not only enrich our knowledge of group Ⅲ droplet epitaxy and facilitate an understanding of provide a solid understanding of such a simple and novel molecular beam epitaxy (MBE) growth process [26].…”

Spectroscopic signatures of many-body interactions and delocalized states in self-assembled lateral quantum dot molecules

“…[10][11][12] The simplest LQDM is a diatomic-like pair of QDs that nucleate from a single site. LQDMs could be the basis of a scalable architecture based on coherent interactions between nearestneighbors, 13,14 but the development and understanding of LQDMs lags behind VQDMs.…”

Coulomb interaction signatures in self-assembled lateral quantum dot molecules

“…To independently control the charge and tunneling, QDMs comprising pairs of laterally separated QDs arranged along axes perpendicular to the growth direction (LQDMs) are of interest. [13][14][15] Parallel and independent control of coupling and charge manipulation in multiple QDMs is a prerequisite for scaling up and building optoelectronic devices that use the QDs as bit registers.…”