Morphology and growth of capped Ge/Si quantum dots

Yizhak Yacoby; Naomi Elfassy; Samit K. Ray; Raj K. Singha; Samaresh Das; Eyal Cohen; Shira Yochelis; Roy Clarke; Yossi Paltiel

doi:10.1007/s11051-013-1608-3

Morphology and growth of capped Ge/Si quantum dots

Yizhak Yacoby, Naomi Elfassy, Samit K. Ray, Raj K. Singha, Samaresh Das, Eyal Cohen, Shira Yochelis, Roy Clarke, Yossi Paltiel

The Hebrew University of Jerusalem

Research output: Contribution to journal › Article › peer-review

Abstract

The morphology, atomic structure, and chemical composition of small (4 nm average height and 20 nm average diameter), dense capped MBE-grown Ge/Si quantum dots are studied using an energy-differential extension of the direct X-ray phasing method, COBRA. Our results lead to the following conclusions: (i) the quantum dot system has a partial wetting layer; (ii) in the lower parts of the dots, the Ge content is small and increases toward the top; and (iii) the contact angle between the dots and the substrate is acute, consistent with the presence of a wetting layer. A growth mechanism compatible with these findings is proposed.

Original language	English
Article number	1608
Journal	Journal of Nanoparticle Research
Volume	15
Issue number	5
DOIs	https://doi.org/10.1007/s11051-013-1608-3
State	Published - May 2013

Keywords

MBE
Nano-crystals
Quantum dots
Self-assembly
X-ray crystallography

All Science Journal Classification (ASJC) codes

Bioengineering
General Chemistry
Atomic and Molecular Physics, and Optics
Modelling and Simulation
General Materials Science
Condensed Matter Physics

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10.1007/s11051-013-1608-3

Cite this

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title = "Morphology and growth of capped Ge/Si quantum dots",

abstract = "The morphology, atomic structure, and chemical composition of small (4 nm average height and 20 nm average diameter), dense capped MBE-grown Ge/Si quantum dots are studied using an energy-differential extension of the direct X-ray phasing method, COBRA. Our results lead to the following conclusions: (i) the quantum dot system has a partial wetting layer; (ii) in the lower parts of the dots, the Ge content is small and increases toward the top; and (iii) the contact angle between the dots and the substrate is acute, consistent with the presence of a wetting layer. A growth mechanism compatible with these findings is proposed.",

keywords = "MBE, Nano-crystals, Quantum dots, Self-assembly, X-ray crystallography",

author = "Yizhak Yacoby and Naomi Elfassy and Ray, \{Samit K.\} and Singha, \{Raj K.\} and Samaresh Das and Eyal Cohen and Shira Yochelis and Roy Clarke and Yossi Paltiel",

note = "Funding Information: Acknowledgments This article is based on research supported as part of the Center for Solar and Thermal Energy Conversion, an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences, under Award \# DE-SC0000957 (x-ray surface scattering), and Israel Science Foundation Grant \# 1005/11 (analysis and modeling). The use of the Advanced Photon Source, an Office of Science User Facility operated for the DOE, Office of Science, by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357. This study was also performed as a part of the program at HUJI Center for Nanoscience and Nanotechnology. The authors are grateful to P. Smereka and J. Mirecki Millunchick for useful discussions.",

year = "2013",

month = may,

doi = "10.1007/s11051-013-1608-3",

language = "الإنجليزيّة",

volume = "15",

journal = "Journal of Nanoparticle Research",

issn = "1388-0764",

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T1 - Morphology and growth of capped Ge/Si quantum dots

AU - Yacoby, Yizhak

AU - Elfassy, Naomi

AU - Ray, Samit K.

AU - Singha, Raj K.

AU - Das, Samaresh

AU - Cohen, Eyal

AU - Yochelis, Shira

AU - Clarke, Roy

AU - Paltiel, Yossi

N1 - Funding Information: Acknowledgments This article is based on research supported as part of the Center for Solar and Thermal Energy Conversion, an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences, under Award # DE-SC0000957 (x-ray surface scattering), and Israel Science Foundation Grant # 1005/11 (analysis and modeling). The use of the Advanced Photon Source, an Office of Science User Facility operated for the DOE, Office of Science, by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357. This study was also performed as a part of the program at HUJI Center for Nanoscience and Nanotechnology. The authors are grateful to P. Smereka and J. Mirecki Millunchick for useful discussions.

PY - 2013/5

Y1 - 2013/5

N2 - The morphology, atomic structure, and chemical composition of small (4 nm average height and 20 nm average diameter), dense capped MBE-grown Ge/Si quantum dots are studied using an energy-differential extension of the direct X-ray phasing method, COBRA. Our results lead to the following conclusions: (i) the quantum dot system has a partial wetting layer; (ii) in the lower parts of the dots, the Ge content is small and increases toward the top; and (iii) the contact angle between the dots and the substrate is acute, consistent with the presence of a wetting layer. A growth mechanism compatible with these findings is proposed.

AB - The morphology, atomic structure, and chemical composition of small (4 nm average height and 20 nm average diameter), dense capped MBE-grown Ge/Si quantum dots are studied using an energy-differential extension of the direct X-ray phasing method, COBRA. Our results lead to the following conclusions: (i) the quantum dot system has a partial wetting layer; (ii) in the lower parts of the dots, the Ge content is small and increases toward the top; and (iii) the contact angle between the dots and the substrate is acute, consistent with the presence of a wetting layer. A growth mechanism compatible with these findings is proposed.

KW - MBE

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KW - Self-assembly

KW - X-ray crystallography

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DO - 10.1007/s11051-013-1608-3

M3 - مقالة

SN - 1388-0764

VL - 15

JO - Journal of Nanoparticle Research

JF - Journal of Nanoparticle Research

IS - 5

M1 - 1608

ER -

Morphology and growth of capped Ge/Si quantum dots

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Keywords

All Science Journal Classification (ASJC) codes

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