Stoichiometry, contamination and microstructure of MnSb(0001) surfaces

• Published in: Applied surface science Vol. 255; no. 6; pp. 3567 - 3575
• Main Authors: Hatfield, S.A., Aldous, J.D., Bell, G.R.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2009
• Subjects: Ferromagnet–semiconductor interface; Half-metal; MBE; MnSb; Surface cleaning; Surface contamination; Wet etching; XPS; Surface cleaning; Wet etching; MBE; MnSb; Surface contamination; Half-metal; XPS; Ferromagnet–semiconductor interface
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2008.09.082

The stoichiometry, microstructure and surface composition of MnSb have been investigated using X-ray photoelectron spectroscopy, electron diffraction and microscopy. Epitaxially grown samples were exposed to ambient air for several weeks and methods for preparing clean, stoichiometric and smooth surfaces were investigated. Air-stored sample surfaces are chemically stratified but dominated by Mn oxides 4–5nm thick. These oxides are difficult to remove by ion bombardment and annealing (IBA), but a brief etch in HCl removes them very efficiently. It leaves the surface Sb-rich, and clean, smooth and stoichiometric surfaces are then readily recovered by IBA. These surfaces exhibit a (2×2) surface reconstruction with atomically flat terraces. This reconstruction can be reversibly changed to a (1×1) by Sb deposition and annealing.