Current Distribution in ESD (Electron Stimulated Desorption) Diodes. Cross Section Corrections,
Abstract
The electron current distribution in diodes consisting of a rectangular crystal and an electron emitting filament parallel to and in front of it, used in several electron stimulated desorption (ESD) experiments has been determined by means of a dummy crystal constructed from uniformly transparent Lektromesh and a moveable, suitably constructed fine probe. It was found that for straight filaments the distribution was uniform along the narrow, but nearly triangular along the long dimension of the crystal. Calculated log signal vs. time curves in ESD show considerable curvature, as often observed experimentally with such geometries. Filaments with a straight center, but coiled and shielded end sections provide uniform current distributions. When such filaments are used the curvature of the log signal vs. t curves disappears for Kr desorption from W(110) but is still seen for oxygen desorption. The absolute fraction of filament current hitting the front surface of a crystal was also determined for various geometries by using a thin suppressor mesh in front of the dummy crystal. Cross sections for CO, O, and Kr ESD from W(110) were redetermined with a coiled end section filament. After correction for the fractions of current to the crystal and current nonuniformities previous results are in fairly reasonable agreement with
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1985
- Accession Number
- ADA163646
Entities
People
- J. C. Lin
- R. Gomer
Organizations
- University of Chicago