Adsorption/desorption kinetics of H[sub 2]O on GaAs(100) measured by photoreflectance
- Department of Chemical Engineering, University of Illinois, Urbana, Illinois 61801 (United States)
The mechanism of H[sub 2]O adsorption on GaAs(100) has been elucidated by an adaptation of the photoreflectance (PR) technique for surface kinetic measurements. Being an optical method, PR is especially well-suited for probing weakly bonded adsorption systems where the pressures required for significant interaction ([gt]10[sup [minus]5] Torr) preclude the use of traditional electron or ion spectroscopies. H[sub 2]O adsorbs through a physisorbed state. This species can desorb or react to a chemisorbed form, which in turn can desorb. Both the physisorbed and chemisorbed species are undissociated. We interpret exceptionally low values for the prefactors associated with the chemisorbed state in terms of an adsorbate-induced surface reconstruction.
- DOE Contract Number:
- FG02-91ER45439
- OSTI ID:
- 5984977
- Journal Information:
- Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 99:9; ISSN JCPSA6; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360606* -- Other Materials-- Physical Properties-- (1992-)
ADSORPTION
ARSENIC COMPOUNDS
ARSENIDES
CHEMICAL REACTIONS
CHEMISORPTION
DESORPTION
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
HYDROGEN COMPOUNDS
KINETICS
LIGHT SCATTERING
OXYGEN COMPOUNDS
PNICTIDES
REFLECTION
SCATTERING
SEPARATION PROCESSES
SORPTION
SORPTIVE PROPERTIES
SURFACE PROPERTIES
WATER