Metal overlayers on organic functional groups of self-organized molecular assemblies. III. X-ray photoelectron spectroscopy of Cr/CN on 12-mercaptododecanenitrile and of Cr/CH[sub 3] on octadecanethiol at sample temperatures from 173 to 373 K
- National Renewable Energy Laboratory (NREL), Golden, Colorado 80401 (United States)
The dependence on substrate temperature of the formation of Cr(CN) complexes and Cr-carbides when Cr overlayers are deposited onto organized molecular assemblies (OMAs) has been investigated [ital in] [ital situ] by x-ray photoelectron spectroscopy (XPS). At Cr coverages of 6 A or less, evidence for the formation of a Cr(CN) complex with the CN end groups of the 12-mercaptododecanenitrile OMA is found in negative binding energy shifts of the nitrile part of the C 1[ital s] line shape and of the N 1[ital s] core level. The N 1[ital s] negative binding energy shift increases from 0.1--1.2 eV for substrate temperatures from 173 to 373 K. At a Cr coverage of 6 A, Cr-carbide was observed to form to a similar extent on the 12-mercaptododecanenitrile and octadecanethiol OMAs. The number of carbide C atoms per OMA chain increases from 0.7 to 3 for substrate temperatures from 173 to 373 K for 6 A Cr on the 12-mercaptododecanenitrile OMA. Greater amounts of carbide result when the Cr is deposited onto a sample at a given temperature, [ital T], than when the deposition at a lower temperature is followed by warming to [ital T]. We interpret the increased amount of carbide to result from a contribution of the incident Cr atom kinetic energy to the activation of the Cr-carbide reaction. Collateral effects of x-ray exposure and substrate temperatures greater than 295 K may have affected, in part, the observed binding energy shifts and peak heights, but do not compromise the general conclusions of our interpretation.
- DOE Contract Number:
- AC36-83CH10093
- OSTI ID:
- 7278047
- Journal Information:
- Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (United States), Journal Name: Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (United States) Vol. 12:4; ISSN 0734-2101; ISSN JVTAD6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360102* -- Metals & Alloys-- Structure & Phase Studies
360602 -- Other Materials-- Structure & Phase Studies
BINDING ENERGY
CHEMICAL REACTIONS
CHROMIUM
ELECTRON SPECTROSCOPY
ELECTRONIC STRUCTURE
ELEMENTS
ENERGY
INTERFACES
METALS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
SPECTROSCOPY
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
TRANSITION ELEMENTS