Effect of oxygen gas pressure on the kinetics of alumina film growth during the oxidation of Al(111) at room temperature

We have studied the effect of oxygen pressure on the self-limiting oxidation of an Al(111) surface at room temperature for oxygen pressures from 1x10-8 to 5 Torr. Using x-ray photoelectron spectroscopy measurements, we monitor the oxidation kinetics and the oxide film thickness for different oxidation times and pressures. After a rapid initial growth stage, the oxide film reaches a saturated thickness, which depends on the oxygen pressure. The kinetic potential, oxide growth rate, oxide film limiting thickness, and the density of oxygen anions on the oxide surface are determined by the measured oxidation kinetics. These quantities show a Langmuir isotherm dependence on the oxygen gas pressure.