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Surface energetics and structure of the Ge wetting layer on Si(100)

Beck, M. J. and van de Walle, A. and Asta, M. (2004) Surface energetics and structure of the Ge wetting layer on Si(100). Physical Review B, 70 (20). Art. No. 205337. ISSN 1098-0121. http://resolver.caltech.edu/CaltechAUTHORS:BECprb04

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Abstract

Ge deposited on Si(100) initially forms heteroepitaxial layers, which grow to a critical thickness of ~3 MLs before the appearance of three-dimensional strain relieving structures. Experimental observations reveal that the surface structure of this Ge wetting layer is a dimer vacancy line (DVL) superstructure of the unstrained Ge(100) dimer reconstruction. In the following, the results of first-principles calculations of the thickness dependence of the wetting layer surface excess energy for the c(4×2) and 4×6 DVL surface reconstructions are reported. These results predict a wetting layer critical thickness of ~3 MLs, which is largely unaffected by the presence of dimer vacancy lines. The 4×6 DVL reconstruction is found to be thermodynamically stable with respect to the c(4×2) structure for wetting layers at least 2 ML thick. A strong correlation between the fraction of total surface induced deformation present in the substrate and the thickness dependence of wetting layer surface energy is also shown.


Item Type:Article
Additional Information:©2004 The American Physical Society. Received 27 January 2004; revised 2 July 2004; published 23 November 2004. This work was supported by the National Science Foundation under Program No. DMR-0102794, and made use of computing resources provided by NPACI at the University of Michigan. The authors also thank P. W. Voorhees for helpful discussions.
Subject Keywords:germanium; silicon; elemental semiconductors; semiconductor epitaxial layers; interface structure; wetting; ab initio calculations; vacancies (crystal); surface reconstruction; surface energy; deformation
Record Number:CaltechAUTHORS:BECprb04
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:BECprb04
Alternative URL:http://dx.doi.org/10.1103/PhysRevB.70.205337
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5122
Collection:CaltechAUTHORS
Deposited By: Lindsay Cleary
Deposited On:02 Oct 2006
Last Modified:26 Dec 2012 09:03

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