Electron binding energy XPS control of n-GaAs with the atomically clean surface etched by Ar+ ions

Cleaning the n-GaAs surface with low-energy Ar+ ions, required in X-ray photoelectron spectroscopy (XPS), has been recently shown to drastically change the core-level binding energies (BEs) of the irradiated surface layer, which prevents the diagnostics of the n-GaAs based semiconductors by the ordinary XPS. Synchrotron-based XPS measurements and modeling of As3d and Ga3d photoemission spectra for an Ar+ - etched n-GaAs wafer made it possible to find conditions for XPS testing the unmodified deep n-GaAs bulk. XPS resolution should be better than 0.5 eV and Ar+ ion energy should be less than 0.5 keV. Control of the Ga3d and As3d BEs in unmodified n-GaAs is important for chemical analysis since they are close to Ga2O3 and elemental arsenic BEs, respectively, which appear in oxidation, nitridation and other important chemical processes.