Characterization with XPS of a Thin Film of B2O2 Deposited on a Ag Substrate

XPS spectra are presented for a thin film of a suboxide of boron formed by condensing B2O2(g) on a clean Ag foil substrate. Spectroscopic characterization of boron suboxides are important as these compounds may exist as surface intermediates in the oxidation of solid boron and of boron compounds. The B2O2(g) source consists of a Knudsen cell in which B(s) and B2O3(s) are heated to 1123 K. Mass spectroscopic analysis confirms that only B2O2(g) effuses from the source. The condensed B2O2 film has a B 1s binding energy of 192.55 eV which allows this boron suboxide to be distinguished from the principal boron oxide B2O3, which has a binding energy of 193.5-194.0 eV [W. C. Foo, J. S. Ozcomert, and M. Trenary, Surf. Sci. 255, 245 (1991)].