The oxidation of the β-rhombohedral boron (111) surface

Abstract

We have studied the reaction of the (111) surface of β-rhombohedral boron with O 2 using X-ray photoelectron spectroscopy (XPS). The surfaces used were clean, as determined with XPS, and well-ordered, as determined with low-energy electron diffraction (LEED). The reaction with O 2 proceeds in two stages, an initial uptake in oxygen followed by a much slower increase in surface oxygen. The net oxygen uptake is low at room temperature, reaches a maximum at 1000–1100 K, and then falls to a low level at 1273 K. To calibrate the oxygen coverage, XPS spectra of the O 2 exposed surface were compared with spectra of B 2O 3 multilayers directly deposited on the surface. The comparison indicates that only submonolayer oxygen coverages are achieved under the conditions used.