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
Research Paper

DOI: 10.1007/s11051-013-1608-3

Cite this article as:
Yacoby, Y., Elfassy, N., Ray, S.K. et al. J Nanopart Res (2013) 15: 1608. doi:10.1007/s11051-013-1608-3
Part of the following topical collections:
  1. Nanostructured Materials 2012. Special Issue Editors: Juan Manuel Rojo, Vasileios Koutsos

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

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

Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  • Yizhak Yacoby
    • 1
  • Naomi Elfassy
    • 2
  • Samit K. Ray
    • 3
  • Raj K. Singha
    • 3
  • Samaresh Das
    • 3
  • Eyal Cohen
    • 2
  • Shira Yochelis
    • 2
  • Roy Clarke
    • 4
  • Yossi Paltiel
    • 2
  1. 1.Racah Institute of PhysicsHebrew UniversityJerusalemIsrael
  2. 2.Department of Applied PhysicsHebrew UniversityJerusalemIsrael
  3. 3.Department of Physics and MeteorologyIndian Institute of Technology KharagpurKharagpurIndia
  4. 4.Applied Physics Program, and Center for Solar and Thermal Energy ConversionUniversity of MichiganAnn ArborUSA

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