AVS 46th International Symposium
    Surface Science Division Monday Sessions
       Session SS1+EM-MoM

Paper SS1+EM-MoM8
The Correlation Between MgO (100) Surface Morphology and Chemical Reactivity

Monday, October 25, 1999, 10:40 am, Room 606

Session: Chemistry on Oxides
Presenter: S.S. Perry, University of Houston
Authors: S.S. Perry, University of Houston
S. Imaduddin, University of Houston
O. El-bjeirami, University of Houston
P.B. Merrill, University of Houston
S.M. Lee, University of Houston
H.I. Kim, University of Houston
Correspondent: Click to Email
A critical ingredient of any surface science study is the preparation of the surface so as to present a uniform and homogeneous distribution of surface sites. For metals, the nature of adsorption site is determined by the crystal face exposed and the local coordination of the different metal atoms at the surface. For compound semiconductors and oxide based materials, the situation can be much more complex as the crystal face and coordination now applies to more than one type of element. The preparation of such materials can be further complicated by the possibility of preferential sputtering of one component of the surface. In this study we have used a combination of microscopy, ex-situ processing, ultrahigh vacuum (UHV) processing and UHV surface analysis to correlate the chemical reactivity of a model metal oxide (MgO) with the nature of surface structure and morphology. Atomic force microscopy, low energy electron diffraction, and reflection high energy electron diffraction studies together have allowed the distinction between amorphous and crystalline surfaces as well as the length scale of surface order. Single crystal MgO(100) surfaces have been prepared by a number of procedures including acid etching, high temperature annealing in ambient pressures of oxygen, UHV annealing, and ion bombardment. The compositional changes of the surface region with respect to these procedures have been followed with X-ray photoelectron spectroscopy. Finally, the chemical reactivity of the MgO(100) surface has been studied using temperature programmed desorption, investigating the desorption properties of water, methanol and carbon monoxide. Together, these studies have generated a complete picture of the relationship between microscopic surface morphology and chemical reactivity for this model metal oxide surface and have highlighted several critical aspects involved in the preparation of single crystal metal oxide surfaces for UHV surface science studies.