Formation of GaAs nanostructures by droplet epitaxy—Monte Carlo simulation

Vasilenko, Maxim A.; Neizvestny, I. G.; Shwartz, Nataliya L.

doi:10.1016/j.commatsci.2015.02.032

Cited by 29 publications

(12 citation statements)

References 34 publications

(48 reference statements)

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“…At the same time, droplet atoms are in equilibrium with the wetting layer, and no concentration gradient appears. However, when the arsenic is supplied to the growth chamber, it covers the surface with an arsenic layer and partially penetrates into the droplets [ 53 ]. In this case, a concentration gradient arises between the arsenic-stabilized surface and metallic droplets, as a result of which a portion of the droplet atoms tend to occupy more energetically favorable positions on the surface arsenic atoms [ 54 ].…”

Section: Resultsmentioning

confidence: 99%

Independent Control Over Size and Surface Density of Droplet Epitaxial Nanostructures Using Ultra-Low Arsenic Fluxes

et al. 2021

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Modern and future nanoelectronic and nanophotonic applications require precise control of the size, shape and density of III-V quantum dots in order to predefine the characteristics of devices based on them. In this paper, we propose a new approach to control the size of nanostructures formed by droplet epitaxy. We reveal that it is possible to reduce the droplet volume independently of the growth temperature and deposition amount by exposing droplets to ultra-low group-V flux. We carry out a thorough study of the effect of arsenic pressure on the droplet characteristics and demonstrate that indium droplets with a large initial size (>100 nm) and a low surface density (<108 cm−2) are able to shrink to dimensions appropriate for quantum dot applications. Small droplets are found to be unstable and difficult to control, while larger droplets are more resistive to arsenic flux and can be reduced to stable, small-sized nanostructures (~30 nm). We demonstrate the growth conditions under which droplets transform into dots, ring and holes and describe a mechanism of this transformation depending on the ultra-low arsenic flux. Thus, we observe phenomena which significantly expand the capabilities of droplet epitaxy.

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Section: Resultsmentioning

confidence: 99%

Independent Control Over Size and Surface Density of Droplet Epitaxial Nanostructures Using Ultra-Low Arsenic Fluxes

et al. 2021

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“…E x is the activation energy for the event x at position r and k B is the Boltzmann constant. This model has been used as the core principle in droplet epitaxy Monte Carlo simulations which have accurately recreated experimental observation [17,20]. Each process rate is limited by intrinsic frequency v x .…”

Section: Resultsmentioning

confidence: 99%

Control of complex quantum structures in droplet epitaxy

Chawner

Chang

Hodgson

et al. 2019

Semicond. Sci. Technol.

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We report the controllable growth of GaAs quantum complexes in droplet molecular-beam epitaxy, and the optical properties of self-assembled AlxGa 1−x As quantum rings embedded in a superlattice. We found that Ga droplets on a GaAs substrate can retain their geometry up to a maximum temperature of 490 • C during post-growth annealing, with an optimal temperature of 320 • C for creating uniform and symmetric droplets. Through controlling only the crystallisation temperature under As 4 in the range of 450 • C to 580 • C, we can reliably control diffusion, adsorption and etching rates to produce various GaAs quantum complexes such as quantum dots, dot pairs and nanoholes. AlxGa 1−x As quantum rings are also realised within these temperatures via the adjustment of As beam equivalent pressure. We found that crystallisation using As 2 molecules in the place of As 4 creates smaller diameter quantum rings at higher density. The photoluminescence of As 2 grown AlxGa 1−x As quantum rings embedded in a superlattice shows a dominant emission from the quantum rings at elevated temperatures. This observation reveals the properties of the quantum ring carrier confinement and their potential application as efficient photon emitters.

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“…[9,10] The peculiarities of simulating the liquid phase in the lattice model are described in previously published work. [14] The processes in the model are specified in accordance with the generally accepted concept of the self-catalytic growth of GaAs NWs. The Ga atoms and the arsenic molecules are deposited on the substrate covered by a mask film layer.…”

Section: Doi: 101002/pssb202100641mentioning

confidence: 99%

“…Besides analytical models, Monte Carlo (MC) simulations can predict the nanostructure morphology. [14][15][16][17][18] The purpose of this work was to analyze the pulsed epitaxial regime for NW growth at low temperature using MC simulation.…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo Simulation of Alternate Pulsed Epitaxial Growth of GaAs Nanowires

Nastovjak

Shterental

Shwartz

2022

Physica Status Solidi (b)

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The Monte Carlo simulation of a self‐catalyzed GaAs nanowire (NW) growth regime is proposed and realized, where gallium and arsenic are deposited in pulsed intervals. Such a pulsed epitaxial growth mode allows low‐temperature epitaxial growth of long GaAs NWs. The influence of gallium and arsenic pulse durations and sequences on the NW morphology is investigated. The catalyst droplet size and contact angle, as well as the diffusion length of Ga adatoms along the NW sidewalls, determine the wire morphology. For a dense NW array, the arsenic readsorption starts to affect the NW growth. The influence of arsenic readsorption on the formation of Ga liquid droplets on the NW sidewalls is investigated with the help of annealing simulations. The significant role of the mass transfer of evaporated materials is demonstrated for GaAs NW morphology.

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Formation of GaAs nanostructures by droplet epitaxy—Monte Carlo simulation

Cited by 29 publications

References 34 publications

Independent Control Over Size and Surface Density of Droplet Epitaxial Nanostructures Using Ultra-Low Arsenic Fluxes

Independent Control Over Size and Surface Density of Droplet Epitaxial Nanostructures Using Ultra-Low Arsenic Fluxes

Control of complex quantum structures in droplet epitaxy

Monte Carlo Simulation of Alternate Pulsed Epitaxial Growth of GaAs Nanowires

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