XPS analysis of surface compositional changes in InSb1-xBix (111) due to low-energy Ar+ ion bombardment

Surface compositional changes induced by multistep 0.2-1.0 keV Ar+ ion bombardment and subsequent annealing of the single crystalline (111) InSb1-xBix (x congruent to 0.005) epitaxial layer have been studied for the first time by X-ray photoelectron spectroscopy (XPS). Application of Ar+ ion beam with energy less than or equal to 0.5 keV produced only a slight increase of the Sb/In concentration ratio above 1.0. On the other hand, 1 keV Ar+ bombardment was found as the most efficient preparation step which led to the removal of the surface oxide (identified here as Sb2Ox), severe reduction of surface carbon content, but also to a decrease of Sb/In ratio towards anion deficiency (Sb/In < 0.8). Subsequent short time anneal at 310 degrees C became sufficient to reach nearly stoichiometric Sb/In ratio in the surface region. Final XPS measurements of the sputter-cleaned and annealed surface revealed that admiring of Bi into InSb does not shift the binding energies of Sb 3d and In 3d core-levels of the host compound. The binding energy of Bi 4f in InSb1-xBix was found to be the same as in elemental Bi. (C) 2000 Elsevier Science B.V. All rights reserved.