Mechanism of Exoelectron Emission From Solid Surfaces.
Abstract
Using sensitive single-particle and single-photon detectors, combined with magnetic discrimination techniques, it is shown that electrons, positive and negative ions, and photons are all emitted simultaneously when rupture of the superficial oxide film occurs during tensile deformation of oxide-covered metals. With compact adherent, anodically-grown Al2O3 films on Al and dense thermally-grown NiO films on Ni, the major fraction of the emitted particles are low energy electrons. Particle emission is believed to originate from crack surfaces in the oxide film. The dependence of the electron emission yield on oxide thickness has been established for dense anodic oxide films up to 2000 A thick on Al. It is also found that the total or integrated yield for 2000 A thick oxide films decreases in the order Al to ni to Ti. The tribostimulated electrons exhibit a rather broad energy spectrum which is definitely non-Maxwellian. The emission behavior is also found to depend strongly on the conditions under which anodic oxide films are grown. It is tentatively suggested that the emission observed from dense oxide films may be primarily of thermionic origin, the needed excitation energy being provided by the elastic strain energy stored in the oxide film that is released during fracture of the film. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1976
- Accession Number
- ADA029551
Entities
People
- L. Himmel
- Peter F. Braeunlich
Organizations
- Wayne State University