Surface water reactivity of polycrystalline MgO and CaO films investigated using x-ray photoelectron spectroscopy

H. S. Craft, R. Collazo, M. D. Losego, Z. Sitar, J. P. Maria

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The authors report a study comparing the surface reactivities of the alkaline earth oxides MgO and CaO with respect to water vapor under ultrahigh and high vacuum conditions. Using x-ray photoelectron spectroscopy and a series of in vacuo exposures spanning ∼ 10-10 Torr vacuum, to 10 -6 Torr flowing oxygen, the extent of surface hydroxylation was investigated by monitoring the O 1s photoelectron line. After the most aggressive exposures, the MgO surface reacted to form a maximum hydroxyl coverage of ∼1.3 ML (monolayer), while the CaO surface reached a maximum coverage of ∼3.0 ML. Both surface hydroxides could be removed by in vacuo thermal anneals; exposure to 250 and 500 °C were required for MgO and CaO, respectively. These results are framed in terms of the suitability of these oxides in complex oxide-compound semiconductor heteroepitaxial multifunctional devices and with respect to understanding the development of surface morphology in epitaxial 111-oriented CaO and MgO thin films.

Original languageEnglish (US)
Pages (from-to)1507-1510
Number of pages4
JournalJournal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Issue number6
StatePublished - Nov 10 2008


All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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