Morphology, surface core-level shifts and surface energy of the faceted GaAs(112)A and (1̄1̄2̄)B surfaces

Jacobi, K.; Platen, J.; Setzer, Carsten; Maárquez, J.; Geelhaar, Lutz; Meyne, C.; Richter, Wolfgang; Kley, Alexander; Ruggerone, Paolo; Scheffler, Matthias

doi:10.1016/s0039-6028(99)00713-x

Cited by 26 publications

(16 citation statements)

References 21 publications

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“…However, since the ridge contribution decreases as r -2 , we expect that the model including only the surface energy contributions will give accurate NW formation energies for all larger diameter zinc-blende nanowires. ZB {11-2} surfaces were found to be unstable [14] and indeed the NWs expected to have this facet orientation show instead tilted {111} microfacets [8]. In agreement with these experimental observations, we find a much higher formation energy for ZB NWs with {11-2} facets at all radii.…”

Section: Contributions To the Nanowire Formation Energysupporting

confidence: 86%

Structural stability of clean GaAs nanowires grown along the [111] direction

Magri

Rosini

Casetta

2010

Phys. Status Solidi (c)

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Using a first‐principles approach we have calculated the formation energies of small diameter GaAs nanowires (NWs) with both zinc‐blende and wurtzite structure grown along the [111] direction. The section of the wires is hexagonal and the side facets are oriented either {11‐20} and {10‐10} in the case of the wurtzite structure, and {110} and {112} for the zinc‐blende structure. The formation energy of the nanowires as a function of their radius is then interpreted in terms of a model in which the energy contributions from the bulks, the flat surfaces and the ridges are taken explicitly into account. We find that the nanowire stability is mainly explained by the competition between the bulk energy, favoring the zincblende structure and the surface energies favoring the wurtzite structure. We find also that the directly calculated formation energies of some small diameter wurtzite NWs can be reproduced by our model taking into account only the bulk and flat surface contributions. That is, the ridges do not contribute substantially to the nanowire formation energy. Inspection of the ridge structure and band structure reveals that this good agreement occurs when the NWs are semiconducting and the ridges do not add more dangling bonds to the surface with respect to those provided by the sidewalls. Within our model we find the critical diameter for the wurtzite‐zinc‐blende transition at 6.3 nm. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Section: Contributions To the Nanowire Formation Energysupporting

confidence: 86%

Structural stability of clean GaAs nanowires grown along the [111] direction

Magri

Rosini

Casetta

2010

Phys. Status Solidi (c)

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“…Platen and coworkers observed with LEED on the unstable GaAs(112)A surface facets with the orientation ͕124͖. 13,14 Lee et al examined the shape of three-dimensional InAs islands on GaAs͑001͒ with reflection high-energy electron diffraction ͑RHEED͒ and reported bounding facets corresponding to ͕136͖ planes. 16 Hasegawa et al characterized the same material system with STM and concluded that some of the sidewalls have the orientation ͕125͖.…”

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confidence: 99%

Experimental evidence for a stable GaAs surface near (113)

2000

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GaAs surfaces vicinal to ͑113͒ with a continuous range of misorientation angles up to 11.5°in all azimuthal directions were created by grinding a spherical depression into ͑113͒ oriented samples. Thin homoepitaxial layers were grown onto these samples by molecular beam epitaxy ͑MBE͒, and the surfaces were in situ studied by low-energy electron diffraction ͑LEED͒ and scanning tunneling microscopy ͑STM͒. The surface quality in the depression was verified by reproducing LEED patterns of the ͑113͒ and ͑114͒ surfaces. A stable GaAs surface was found that is oriented from ͑113͒ by 9°Ϯ2°towards ͓11 0͔. STM and LEED images of this surface are presented.

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“…The first term, the free energy of the facets, is related to the surface atomic configuration and bonding structure that in particular for high index substrates, results on large area stable facets. [22] The edges energy, E edges , is related to the capillarity curvature. With the aim to calculate E edges in the review on spontaneous formation of periodically ordered nanometer-scale structures on crystal surfaces proposed by Shchukin, [21] the ideal situation where the corrugation is symmetric, is considered.…”

Section: Resultsmentioning

confidence: 99%