Abstract
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 language | English (US) |
|---|---|
| Pages (from-to) | 1507-1510 |
| Number of pages | 4 |
| Journal | Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films |
| Volume | 26 |
| Issue number | 6 |
| DOIs | |
| State | Published - 2008 |
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films