Mechanism for Limiting Thickness of Thin Oxide Films on Aluminum
Artikel i vetenskaplig tidskrift, 2014

A first-principles account of the observed limiting thickness of oxide films formed on aluminum during oxidizing conditions is presented. The results uncover enhanced bonding of oxygen to thin alumina films in contact with metallic aluminum that stems from charge transfer between a reconstructed oxide-metal interface and the adsorbed molecules. The first-principles results are compared with the traditional Cabrera-Mott (CM) model, which is a classical continuum model. Within the CM model, charged surface oxygen species and metal ions generate a (Mott) potential that drives oxidation. An apparent limiting thickness is observed as the oxidation rate decreases rapidly with film growth. The present results support experimental estimates of the Mott potential and film thicknesses. In contrast to the CM model, however, the calculations reveal a real limiting thickness that originates from a diminishing oxygen adsorption energy beyond a certain oxide film thickness.

Författare

J. D. Baran

Henrik Grönbeck

Chalmers, Teknisk fysik, Kemisk fysik

Kompetenscentrum katalys (KCK)

Anders Hellman

Chalmers, Teknisk fysik, Kemisk fysik

Kompetenscentrum katalys (KCK)

Physical Review Letters

0031-9007 (ISSN) 1079-7114 (eISSN)

Vol. 112 14

Styrkeområden

Nanovetenskap och nanoteknik

Transport

Energi

Materialvetenskap

Ämneskategorier

Fysik

Infrastruktur

C3SE (Chalmers Centre for Computational Science and Engineering)

DOI

10.1103/PhysRevLett.112.146103