First principles study of gallium‐cleaning for hydrogen‐contaminated α‐Al 2 O 3 (0001) surfaces

The use of gallium for cleaning hydrogen‐contaminated Al 2 O 3 surfaces is explored by performing first principles density functional calculations of gallium adsorption on a hydrogen‐contaminated Al‐terminated α‐Al 2 O 3 (0001) surface. Both physisorbed and chemisorbed H‐contaminated α‐Al 2 O 3 (0001) surfaces with one monolayer (ML) gallium coverage are investigated. The thermodynamics of gallium cleaning are considered for a variety of different asymptotic products, and are found to be favorable in all cases. Physisorbed H atoms have very weak interactions with the Al 2 O 3 surface and can be removed easily by the Ga ML. Chemisorbed H atoms form stronger interactions with the surface Al atoms. Bonding energy analysis and departure simulations indicate, however, that chemisorbed H atoms can be effectively removed by the Ga ML. © 2013 Wiley Periodicals, Inc.