Indium segregation during III–V quantum wire and quantum dot formation on patterned substrates

Moroni, Stefano T.; Dimastrodonato, V.; Chung, Taek‐Mo; Juška, Gediminas; Gocalinska, Agnieszka; Vvedensky, Dimitri D.; Pelucchi, E.

doi:10.1063/1.4919362

Cited by 11 publications

(15 citation statements)

References 27 publications

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“…These results are based on the AlGaAs/GaAs system. Recently Moroni et al [68] showed that the model appears equally capable of describing In segregation when In-GaAs V-groove quantum wires or pyramidal dots are considered, not only describing accurately previous experimental findings ( Fig. 12(a)), but also explaining a puzzling experimental result in the pyramidal system.…”

Section: Nominalga Contentsupporting

confidence: 52%

“…In the same manuscript an important experimental observation was reported. While until then all models assumed a simple (111)A/(111)B/(111)A structure at the pyramidal center, Moroni et al [68] showed that a more complex faceting at the bottom of pyramidal recesses appears and is indeed necessary to properly link the bottom and lateral facets maintaining crystallographic continuity. This observation is shared in [70], where for the first time a kinetic Monte Carlo simulation of GaAs growth inside pyramidal recesses is attempted.…”

Section: Nominalga Contentmentioning

confidence: 99%

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Self-ordered nanostructures on patterned substrates

Pelucchi

Moroni

Dimastrodonato

et al. 2017

J Mater Sci: Mater Electron

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The formation of nanostructures during metalorganic vapor-phase epitaxy on patterned (001)/(111)B GaAs substrates is reviewed. The focus of this review is on the seminal experiments that revealed the key kinetic processes during nanostructure formation and the theory and modelling that explained the phenomenology in successively greater detail. Experiments have demonstrated that V-groove quantum wires and pyramidal quantum dots result from self-limiting concentration profiles that develop at the bottom of V-grooves and inverted pyramids, respectively. In the 1950s, long before the practical importance of patterned substrates became evident, the mechanisms of capillarity during the equilibration of non-planar surfaces were identified and characterized. This was followed, from the late 1980s by the identification of growth rate anisotropies (i.e. differential growth rates of crystallographic facets) and precursor decomposition anisotropies, with parallel developments in the fabrication of V-groove quantum wires and pyramidal quantum dots. The modelling of these growth processes began at the scale of facets and culminated in systems of coupled reaction-diffusion equations, one for each crystallographic facet that defines the pattern, which takes account of the decomposition and surface diffusion kinetics of the group-III precursors and the subsequent surface diffusion and incorporation of the group-III atoms released by these precursors. Solutions of the equations with optimized parameters produced concentration profiles that provided a quantitative interpretation of the time-, temperature-, and alloy-concentration dependence of the self-ordering process seen in experiments.

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Section: Nominalga Contentsupporting

confidence: 52%

Section: Nominalga Contentmentioning

confidence: 99%

Self-ordered nanostructures on patterned substrates

Pelucchi

Moroni

Dimastrodonato

et al. 2017

J Mater Sci: Mater Electron

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“…1a). The structure comprises a number of differently composed III-V (Al)GaAs layers and an InGaAs QD layer (see Supplementary Material for a detailed description of each layer, and the reasons for inserting them)all obeying complex epitaxial dynamics as reported elsewhere 19,20,21,22 . The outcome is an ensemble of self-forming nanostructures inside each pyramidal recess, described by the generic sketches in Fig.…”

Section: Pyramidal Quantum Dot Systemmentioning

confidence: 99%

Selective carrier injection into patterned arrays of pyramidal quantum dots for entangled photon light-emitting diodes

et al. 2016

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Scalability and foundry compatibility (as for example in conventional silicon based integrated computer processors) in developing quantum technologies are exceptional challenges facing current research. Here we introduce a quantum photonic technology potentially enabling large scale fabrication of semiconductor-based, site-controlled, scalable arrays of electrically driven sources of polarization-entangled photons, with the potential to encode quantum information. The design of the sources is based on quantum dots grown in micron-sized pyramidal recesses along the crystallographic direction (111)B theoretically ensuring high symmetry of the quantum dotsthe condition for actual bright entangled photon emission. A selective electric injection scheme in these non-planar structures allows obtaining a high density of light-emitting diodes, with some producing entangled photon pairs also violating Bell's inequality. Compatibility with semiconductor fabrication technology, good reproducibility and control of the position make these devices attractive candidates for integrated photonic circuits for quantum information processing.To develop quantum technologies, the scientific community is looking into several alternative practical routes, varying as much as superconducting qubits, atoms on-chips, photonic integrated circuits and others 1,2,3,4 . All the explored technologies have to solve the scalability and reproducibility problem if they are to deliver successful real-life applications. In the case of the photonic quantum technologies, scalability requires moving from discrete optical elements to integrated photonic circuits and to on-chip solid-state sources, allowing, for example, thousands of units operating in unisona condition which is very hard to fulfil at the moment.Semiconductor quantum dot technology is fundamentally compatible with modern fab/foundry processes, and on-demand identical, single and entangled photons have been all demonstrated by optical pumping 5,6,7,8,9,10,11,12,13,14 . Nevertheless, while the development of electrically pumped (EP) quantum light sources has advanced in general 15 , the development of a particular resource, EP entangled photon sources, has proven more challenging. After the first report in Nature 16 , the community had to wait several years before a similar result could be obtained by other groups 17 . Importantly, the few devices reported to date, utilized epitaxial selfassembled QD structures, i.e. with no control on the source location, nor on the number of sources in a single device (typically hundreds or more, and not just one or, in the best case scenario, a few): a critical aspect for photonic integration scaling.

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“…We pause here a second, to stress the relevance and unique control demonstrated by these results. Indeed the peculiarity of the MOVPE III-V growth process utilized here [20] [29] allows what is a uniquely demonstrated control over uniformity and dot reproducibility [30], which should be ascribed to the distinctive MOVPE processes involved in a concave environment (i.e. decomposition rate anisotropy and specific adatom diffusion/capillarity processes/anisotropies).…”

Section: Resultsmentioning

confidence: 94%

Vanishing biexciton binding energy from stacked, MOVPE grown, site-controlled pyramidal quantum dots for twin photon generation

Moroni

Varo

Juška

et al. 2019

Journal of Crystal Growth

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We characterized stacked double-pyramidal quantum dots which showed biexciton binding energies close to zero by means of photoluminescence and cross-correlation measurements. It was possible to obtain a sequence of two photons with (nearly) the same energy from the biexciton-exciton-ground state cascade, as corroborated by a basic rate-equation model. This type of two-photon emission is both of relevance for fundamental quantum information theory studies as well as for more exotic applicative fields such as quantum biology.

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Indium segregation during III–V quantum wire and quantum dot formation on patterned substrates

Cited by 11 publications

References 27 publications

Self-ordered nanostructures on patterned substrates

Self-ordered nanostructures on patterned substrates

Selective carrier injection into patterned arrays of pyramidal quantum dots for entangled photon light-emitting diodes

Vanishing biexciton binding energy from stacked, MOVPE grown, site-controlled pyramidal quantum dots for twin photon generation

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