Preparation and properties of clean surfaces of aluminum

Abstract

A low-energy electron diffraction study of clean {111}, {100} and {110} surfaces of aluminum and their reaction with oxygen is described. The procedures followed in order to achieve the atomically clean state were: (i) argon ion bombardments and anneals, (ii) baking in atomic hydrogen and (iii) growth of epitaxial films in situ. All three surfaces investigated have the ideal structure expected from simple termination of the bulk. Chemisorption of dry or wet oxygen at room temperature occurs in disordered fashion and gives rise to amorphous layers, probably by way of place-exchange mechanisms. The sticking coefficient of oxygen is estimated to be 10-3-10-2. Epitaxy of aluminum is found to be good at room temperature on all three surfaces investigated. On {110} surfaces, as-deposited films exhibit {111} facets. © 1967.