Cross-sectional scanning tunneling microscopy study of InGaAs quantum dots on GaAs(001) grown by heterogeneous droplet epitaxy

Liu, N.; Lyeo, Ho-Ki; Shih, Chih‐Kang; Oshima, Masaharu; Mano, Takaaki; Koguchi, Nobuyuki

doi:10.1063/1.1479196

Cited by 18 publications

(9 citation statements)

References 21 publications

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“…58(a) where the growth direction is from bottom to top. In a similar way, the composition of InGaAs quantum dots on GaAs(001) grown by heterogeneous droplet epitaxy has been determined to be 17% in average [154], and an atomically resolved compositional map of a GaAs/AlGaAs quantum dot grown by droplet epitaxy has been obtained (a concentration of Al of 6% was found) [155].…”

Section: Cross-sectional Studies Of Buried Quantum Dots and Ringsmentioning

confidence: 99%

Compositional mapping of semiconductor quantum dots and rings

Biasiol

Heun

2011

Physics Reports

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Section: Cross-sectional Studies Of Buried Quantum Dots and Ringsmentioning

confidence: 99%

Compositional mapping of semiconductor quantum dots and rings

Biasiol

Heun

2011

Physics Reports

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“…Meanwhile, such experiments of in situ cleaved samples have been extended towards epitaxial layers of gallium arsenide‐based structures, as have been reported e.g. GaAs/AlGaAs multilayers and interfaces 8, GaAs/AlAs superlattices 9, composition profiles in indium gallium arsenide quantum dots 10, counting of single indium atoms in a gallium arsenide matrix 11, examining nanovoids in indium gallium arsenide quantum dots 12 or studying capping processes of indium arsenide quantum dots 13.…”

Section: Introductionmentioning

confidence: 99%

Atomic structure of the non‐polar GaN($ \bar 2 $110) surface by cross‐sectional scanning tunneling microscopy

Krüger

Kuhr

Schmidt

et al. 2009

Physica Rapid Research Ltrs

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The ($ \bar 2 $110) plane of gallium nitride, exposed by cleaving a GaN single crystal under ultra‐high vacuum conditions, has been atomically resolved for the first time, using cross‐sectional scanning tunneling microscopy. The spatial period length supports a (1 × 1) unit mesh size, i.e., the absence of a reconstruction. The contrast observed in the experimental data is well explained by the atomic arrangement expected for a truncated‐bulk structure. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…On the other hand, measurements of spectroscopic properties of a dot 1,2,3,4,5,6 are rarely accompanied by accurate measurements of the size and shape of the GaAs-covered dot, except in rare cases where detailed cross-sectional scanning tunneling microscopy experiments are performed, such as in Refs. 15,16,17. This situation creates a significant difficulty, if not a crisis, in interpreting spectroscopic data on quantum dots, and in critically testing various theoretical approaches.…”

Section: Introductionmentioning

confidence: 99%

Dependence of the electronic structure of self-assembled (In,Ga)As∕GaAs quantum dots on height and composition

Narvaez

Bester

Zunger

2005

Journal of Applied Physics

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While electronic and spectroscopic properties of self-assembled In1−xGaxAs/GaAs dots depend on their shape, height and alloy compositions, these characteristics are often not known accurately from experiment. This creates a difficulty in comparing measured electronic and spectroscopic properties with calculated ones. Since simplified theoretical models (effective mass, k·p, parabolic models) do not fully convey the effects of shape, size and composition on the electronic and spectroscopic properties, we offer to bridge the gap by providing accurately calculated results as a function of the dot height and composition. Prominent features of our results are the following. (i) Regardless of height and composition, the confined electron energy levels form shells of nearly degenerate states with a predominant orbital "s", "p", · · · character. In contrast, the confined hole energy levels form shells only in flat dots and near the highest hole level (HOMO). (ii) In alloy dots, the electrons' "s-p" splitting depends weakly on height, while the "p-p" splitting depends non-monotonically-due to alloy fluctuations. In pure, non-alloyed InAs/GaAs dots, both these splittings depend weakly on height. Further, the "s-p" splitting is larger while the "p-p" has nearly the same magnitude. For holes levels in alloy dots, the "s-p" splitting decreases with increasing height (the splitting in tall dots being about 4 times smaller than in flat dots), whereas the "p-p" splitting remains nearly unchaged. Shallow, pure non-alloyed dots have a "s-p" splitting of nearly the same magnitude, whereas the "p-p" splitting is about three times larger. (iii) As height increases, the "s" and "p" character of the wavefunction of the HOMO becomes mixed, and so does the heavy-and light-hole character. (iv) In alloy dots, regardless of height, the wavefunction of low-lying hole states are localized inside the dot. Remarkably, in non-alloyed InAs/GaAs dots these states become localized at the interface as height increases. The localized states are nearly degenerate and polarized along [110] and [110]. This localization is driven by the peculiarities of the biaxial strain present in the nanostructure.

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Cross-sectional scanning tunneling microscopy study of InGaAs quantum dots on GaAs(001) grown by heterogeneous droplet epitaxy

Cited by 18 publications

References 21 publications

Compositional mapping of semiconductor quantum dots and rings

Compositional mapping of semiconductor quantum dots and rings

Atomic structure of the non‐polar GaN($ \bar 2 $110) surface by cross‐sectional scanning tunneling microscopy

Dependence of the electronic structure of self-assembled (In,Ga)As∕GaAs quantum dots on height and composition

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