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The interaction of Si with Al(111) surfaces above room temperature
A402 204
Surface Science 189,/190 (1987) 204-210 North-Holland, Amsterdam
THE INTERACTION
O F Si W I T H
AI(Ill)
SURFACES
ABOVE ROOM TEMPERATURE M.C. MUNOZ,
F. S O R I A a n d J.L. S A C E D O N
lnstituto de Ciencia de Materiales (CSIC), Serrano 144, E-28006 Madrid, Spain Received 27 March 1987; accepted for publication 15 April 1987 The interaction of Si with AI(lll) surfaces heated up to 523 K is investigated by means of AES, LEED, and ELS. Although at room temperature Si chemisorbs following a layer-by-layer growth up to two monolayers (ML), upon heating at temperatures as low as 310 K the second Si ML undergoes structural changes resulting in a Stranski-Krastanov-type of growth. At higher temperatures Si diffuses into the AI lattice with an activation energy of 1.21 eV. The Auger transition density of states and ELS spectra support a model in which the in-diffused Si forms clusters in the A1 matrix, in agreement with the low solubility of Si at temperatures lower than 523 K.
Surface Science 189/190 (1987) 211-220 North-Holland, Amsterdam
211
A STUDY OF THE ADSORPTION
AND DECOMPOSITION
OF d4-ETHENE ON MODEL BIMETALLIC Au/Ru(0001) SURFACES USING SSIMS AND EELS B. S A K A K I N I , N . D U N H I L L , a n d J.C. V I C K E R M A N
C. H A R E N D T
*, B. S T E E P L E S
Surface Analysis Research Centre, Department of Chemistry, Uniuersi(v of Manchester Institute of Science and Technology, Manchester M60 1QD, UK Received 12 April 1987; accepted for publication 16 April 1987 A study of the adsorption and decomposition of d4-ethene on Ru(0001) and Au/Ru(0001) bimetallic surfaces is described. EELS shows that di-o adsorption occurs at 130 K on Ru. Increasing Au coverages progressively inhibit this adsorption, but the mechanism switches to rr-bonding. Ethene will adsorb on a Au layer on Ru up to a coverage of 2 ML, beyond this coverage adsorption is suppressed. As surface temperature is increased to 230 K the di-o bonded ethene decomposes to ethylidyne. SSIMS data confirms this sequence but adds further detail firstly regarding the adsorption at 130 K, Ru seems to play the predominant role in both the di-o and ~r adsorption, secondly in the decomposition the influence of Au is progressive but most significant below 0.4 ML.
Surface Science 189,/190 (1987) 204-210 North-Holland, Amsterdam
THE INTERACTION
O F Si W I T H
AI(Ill)
SURFACES
ABOVE ROOM TEMPERATURE M.C. MUNOZ,
F. S O R I A a n d J.L. S A C E D O N
lnstituto de Ciencia de Materiales (CSIC), Serrano 144, E-28006 Madrid, Spain Received 27 March 1987; accepted for publication 15 April 1987 The interaction of Si with AI(lll) surfaces heated up to 523 K is investigated by means of AES, LEED, and ELS. Although at room temperature Si chemisorbs following a layer-by-layer growth up to two monolayers (ML), upon heating at temperatures as low as 310 K the second Si ML undergoes structural changes resulting in a Stranski-Krastanov-type of growth. At higher temperatures Si diffuses into the AI lattice with an activation energy of 1.21 eV. The Auger transition density of states and ELS spectra support a model in which the in-diffused Si forms clusters in the A1 matrix, in agreement with the low solubility of Si at temperatures lower than 523 K.
Surface Science 189/190 (1987) 211-220 North-Holland, Amsterdam
211
A STUDY OF THE ADSORPTION
AND DECOMPOSITION
OF d4-ETHENE ON MODEL BIMETALLIC Au/Ru(0001) SURFACES USING SSIMS AND EELS B. S A K A K I N I , N . D U N H I L L , a n d J.C. V I C K E R M A N
C. H A R E N D T
*, B. S T E E P L E S
Surface Analysis Research Centre, Department of Chemistry, Uniuersi(v of Manchester Institute of Science and Technology, Manchester M60 1QD, UK Received 12 April 1987; accepted for publication 16 April 1987 A study of the adsorption and decomposition of d4-ethene on Ru(0001) and Au/Ru(0001) bimetallic surfaces is described. EELS shows that di-o adsorption occurs at 130 K on Ru. Increasing Au coverages progressively inhibit this adsorption, but the mechanism switches to rr-bonding. Ethene will adsorb on a Au layer on Ru up to a coverage of 2 ML, beyond this coverage adsorption is suppressed. As surface temperature is increased to 230 K the di-o bonded ethene decomposes to ethylidyne. SSIMS data confirms this sequence but adds further detail firstly regarding the adsorption at 130 K, Ru seems to play the predominant role in both the di-o and ~r adsorption, secondly in the decomposition the influence of Au is progressive but most significant below 0.4 ML.