Sputter cleaning and annealing of zinc-blende MnTe surface—XPS study

This paper, being a complementary one to our earlier report (Chem. Phys. Lett. 387 (2004) 110), presents a detailed description of the surface cleaning method applied for molecular beam epitaxy (MBE)-grown zinc-blende (zb)-MnTe epilayers. In particular, surface compositional changes induced by multistep Ar+ ion sputtering (with beam energy, Ei, fixed between 0.5 and 2.0 keV) and subsequent annealing of zb-MnTe crystal have been studied by using X-ray photoelectron spectroscopy (XPS). It was found that Ar+ ion bombardment with Ei = 1.5 keVappeared as the crucial preparation step (either in multistep- or in postanneal sputtering), which provided an efficient removal of the surface oxides and contaminants and led to nearly stoichiometric surface composition, namely [Te]/[Mn] = 0.97. Detailed analysis of the Mn 2p core-level spectrum (acquired in Mg Ka mode) for clean zb-MnTe surface exhibited good consistency with the results of the relevant analysis reported earlier (see the reference above)