Prediction of the atomic structure and stability for the ensemble of silicon nanoclusters passivated by hydrogen

¹ P.N. Lebedev Physical Institute, Russian Academy of Sciences - 119991 Leninskii prosp. 53, Moscow, Russia
² Department of Geosciences, Center for Materials by Design, and Institute for Advanced Computational Science, State University of New York - Stony Brook, NY 11794-2100, USA
³ Moscow Institute of Physics and Technology - Dolgoprudny, Moscow Region 141700, Russia
⁴ Northwestern Polytechnical University - Xi'an, Shaanxi 710072, PRC

^(a) baturin@lpi.ru

Received: 8 December 2013
Accepted: 10 April 2014

Abstract

The total energy and geometry of nanoclusters are calculated using evolutionary structure searching and density functional theory. The calculation shows that the arrangement of Si atoms is close to the diamond crystal structure only in the cluster , while in others it is unique for each composition. We found that the ensemble of clusters remains uniform after passivation only if hydrogen concentration corresponds to one of the stable compositions – , , , or . Passivation by an arbitrary amount of hydrogen converts the ensemble into a mixture of the stable clusters having the nearest compositions. In addition there are numerous metastable cluster configurations with energies within above the ground state. These metastable configurations come into existence in synthesis at , making experimentally realizable cluster compositions even more diverse.