by José Emilio Prieto and Ivan Markov
Abstract:
The transformation of monolayer islands into bilayer islands as a first step of the overall two-dimensional to three-dimensional (2D-3D) transformation in the coherent Stranski-Krastanov mode of growth is studied for the cases of expanded and compressed overlayers. Compressed overlayers display a nucleation-like behavior: The energy accompanying the transformation process displays a maximum at some critical number of atoms, which is small for large enough values of the misfit, and then decreases gradually down to the completion of the transformation, nonmonotonically due to the atomistics of the process. On the contrary, the energy change in expanded overlayers increases up to close to the completion of the transformation and then abruptly collapses with the disappearance of the monoatomic steps to produce low-energy facets. This kind of transformation takes place only in materials with strong interatomic bonding. Softer materials under tensile stress are expected to grow predominantly with a planar morphology until misfit dislocations are introduced, or to transform into 3D islands by a different mechanism. It is concluded that the coherent Stranski-Krastanov growth in expanded overlayers is much less probable than in compressed ones for kinetic reasons.
Reference:
José Emilio Prieto and Ivan Markov, “Quantum-dot nucleation in strained-layer epitaxy: Minimum-energy pathway in the stress-driven two-dimensional to three-dimensional transformation”, Physical Review B, vol. 72, no. 20, pp. 205412.
Bibtex Entry:
@article{prieto_quantum-dot_2005,
title = {Quantum-dot nucleation in strained-layer epitaxy: {Minimum}-energy pathway in the stress-driven two-dimensional to three-dimensional transformation},
volume = {72},
shorttitle = {Quantum-dot nucleation in strained-layer epitaxy},
url = {https://link.aps.org/doi/10.1103/PhysRevB.72.205412},
doi = {10.1103/PhysRevB.72.205412},
abstract = {The transformation of monolayer islands into bilayer islands as a first step of the overall two-dimensional to three-dimensional (2D-3D) transformation in the coherent Stranski-Krastanov mode of growth is studied for the cases of expanded and compressed overlayers. Compressed overlayers display a nucleation-like behavior: The energy accompanying the transformation process displays a maximum at some critical number of atoms, which is small for large enough values of the misfit, and then decreases gradually down to the completion of the transformation, nonmonotonically due to the atomistics of the process. On the contrary, the energy change in expanded overlayers increases up to close to the completion of the transformation and then abruptly collapses with the disappearance of the monoatomic steps to produce low-energy facets. This kind of transformation takes place only in materials with strong interatomic bonding. Softer materials under tensile stress are expected to grow predominantly with a planar morphology until misfit dislocations are introduced, or to transform into 3D islands by a different mechanism. It is concluded that the coherent Stranski-Krastanov growth in expanded overlayers is much less probable than in compressed ones for kinetic reasons.},
number = {20},
urldate = {2017-07-21},
journal = {Physical Review B},
author = {Prieto, José Emilio and Markov, Ivan},
month = nov,
year = {2005},
pages = {205412},
file = {APS Snapshot:E:\cmam_papers\files\477\PhysRevB.72.html:text/html;APS Snapshot:E:\Usuarios\Administrator\Zotero\storage\G66RV98F\PhysRevB.72.html:text/html},
}