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First-Principles Dynamics of Fluorine Adsorption on Clean and Monohydrogenated Si{001}.

Published version
Peer-reviewed

Type

Article

Change log

Authors

Wu, Ian YH 

Abstract

The interaction of highly reactive species with solid surfaces can result in modes of adsorption quite distinct from the classic molecular and dissociative events that are usually thought to dominate. For instance, compelling experimental evidence suggests that adsorption of F2 at the Si{001} surface is often initiated by abstraction (and binding at the surface) of just one fluorine atom from the molecule; the second fluorine atom subsequently experiences either a separate atomic adsorption event or ejection from the surface altogether. Molecular dynamics simulations using empirical potentials support this concept but massively overestimate the prevalence of atomic ejection. In this work, we report first-principles molecular dynamics calculations that correctly show atomic ejection to be rare while providing insight into the details of abstractive adsorption. In addition, we also examine the case of F2 adsorption onto a monohydrogenated Si{001} surface, finding evidence for a different type of abstractive adsorption, in which a hydrogen atom may be removed from the surface to form a short-lived HFF intermediate. The latter rapidly decomposes to produce either HF or (via reaction with another surface hydrogen atom) H2.

Description

Keywords

51 Physical Sciences, 34 Chemical Sciences, 5102 Atomic, Molecular and Optical Physics, 3406 Physical Chemistry

Journal Title

Langmuir

Conference Name

Journal ISSN

0743-7463
1520-5827

Volume Title

38

Publisher

American Chemical Society (ACS)