Accession Number:

ADA080908

Title:

The Role of Steps and Defects in Electron Stimulated Desorption: Oxygen on Stepped W (110) Surfaces.

Descriptive Note:

Interim technical rept.,

Corporate Author:

NATIONAL BUREAU OF STANDARDS WASHINGTON DC SURFACE SCIENCE DIV

Personal Author(s):

Report Date:

1980-01-20

Pagination or Media Count:

51.0

Abstract:

In order to examine the role of atomic steps and defects on electron stimulated desorption ESD phenomena, we have studied the adsorption of oxygen on a polyhedral tungsten crystal containing a W110 flat and 4 flats having orientations 6 deg and 10 deg off the 110 plane with rows of steps parallel to the 100 and 110 directions. Upon adsorption at 300K, there is little or no ESD O emission from the oxygen-covered 110 plane. In contrast, the stepped surfaces yield intense O emission normal to the terraces and in downstep directions, as seen using electron stimulated desorption ion angular distributions ESDIAD. The presence of atomic steps has a major influence on sticking probability, saturation oxygen coverage and the ESDIAD patterns at all adsorption temperatures in the range 100K to greater than or approximately 1400K. Adsorption at low coordination sites appears to be a key factor in producing high ESD ion yields. Author

Subject Categories:

  • Physical Chemistry
  • Crystallography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE