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Defects, Energies, Hydrogen, and Structural Properties of Molecular-Dynamics Modeled a-Si:H

Published online by Cambridge University Press:  15 February 2011

P. A. Fedders*
Affiliation:
Department of Physics, Washington University, St. Louis, MO 63130
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Abstract

We use ab initio pseudopotential local-density-approximation methods to create and study related supercells containing 62 Si atoms and from 5 to 7 H atoms. In particular, we obtain energies and structural properties of H in different charge states that are passivating dangling bonds, in bond centered positions, and in other interstitial sites. The most striking result found is the rather large (of order 1 eV) spread of energies for a given type of defect, depending on its surroundings. We also find that changes in single particle energies or energy eigenvalues from defect to defect are not particular close to changes in the total energy and that the distinction, between bond centered H and a dangling bond plus an Si-H bond, is not as clear cut as one might think. The calculations also provide insights into possible migration mechanisms and energies for H movement.

Type
Research Article
Copyright
Copyright © Materials Research Society 1995

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References

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