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Physics and AstronomyAtomic and Molecular Physics and Spectroscopy

Direct Dimer-by-Dimer Identification of Clean and Monohydride Dimers on the Si(001) Surface by Scanning Tunneling Microscopy

Authors: Y. Wang; M. Bronikowski; R. J. Hamers; WISCONSIN UNIV-MADISON DEPT OF CHEMISTRY
Abstract:
Atomic resolution images of clean Si(001)-(2x1) and the mono-hydride phase, Si(001)-(2xl)H were investigated using scanning tunneling microscopy at various sample-tip bias voltages. At a sample-tip bias of -1.9 V, each dimer of the monohydride phase show two protrusions 3.3 A apart separated by a minimum 0. 11 A deep for a sample bias of -1.9 Volt, while clean dimers show a single protrusion per unit cell. Monohydride dimers appear lower than clean dimers, with apparent height differences ranging from 1.9 A at -1.6 V to 0.65 A at -3.0 V sample bias. An analysis of the apparent height and spatial distribution of tunneling current within each dimer can be used to unambiguously discriminate between clean dimers, monohydride dimers, and vacancy defects. This methodology is applied to study the distribution using disilane, revealing segregation of the monohydride into nearly isotropic islands.

Limitations: APPROVED FOR PUBLIC RELEASE
Description: Interim rept. 1 Jun 93-31 May 94
Pages: 28
Report Date: 27 MAY 94
Contract Number: N00014-91-J-1629
Report Number: A851082
Keywords relating to this report:
*DIMERS
*Hydrides
*HYDROGEN
*IDENTIFICATION
*MICROSCOPY
*SCANNING
*SILICON
*SURFACES
*TUNNELING
ATOMIC STRUCTURE
BIAS
CELLS
CURRENTS
EPITAXIAL GROWTH
HEIGHT
IMAGES
METHODOLOGY
PHASE
RESOLUTION
SILANES
SPATIAL DISTRIBUTION
VACANCIES_CRYSTAL DEFECTS_
VOLTAGE
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