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Low coverage spontaneous etching and hyperthermal desorption of aluminum chlorides from Cl2/Al(111)
- Source :
- The Journal of chemical physics. 121(18)
- Publication Year :
- 2004
-
Abstract
- Nonresonant multiphoton ionization with time-of-flight mass spectrometry has been used to monitor the desorption of aluminum chloride (Al(x)Cl(y)) etch products from the Al(111) surface at 100 and 500 K during low-coverage (5% monolayer) monoenergetic Cl(2) (0.11-0.65 eV) dosing. The desorption products in this low-coverage range show predominantly hyperthermal exit velocities under all dosing conditions. For example, with 0.27 eV incident Cl(2), the etch product was found to have a most-probable velocity of 517+/-22 m/s at an Al(111) surface temperature of 100 K. This corresponds to 22 times the expected thermal desorption translational energy for AlCl(3). Cl(2) sticking probability measurements and Al(x)Cl(y) etch rate measurements show etching even at Cl(2) coverages of less than 5% monolayer at surface temperatures between 100 and 500 K. These experimental results are consistent with a combination of fast-time-scale surface diffusion and agglomeration of the adsorbed chlorine to form aluminum chlorides and the presence of activated AlCl(3) chemisorption states having potential energies above the vacuum level. Density functional theory calculations yield results that are consistent with both our experimental findings and mechanistic descriptions.
- Subjects :
- Hot Temperature
Time Factors
Surface Properties
Analytical chemistry
Thermal desorption
General Physics and Astronomy
Mass spectrometry
Diffusion
Chlorides
Ionization
Desorption
Monolayer
Aluminum Chloride
Physical and Theoretical Chemistry
Aluminum Compounds
Surface diffusion
Photons
Models, Statistical
Chemistry
Chemistry, Physical
Temperature
Models, Chemical
Chemisorption
Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
Adsorption
Sticking probability
Chlorine
Software
Aluminum
Subjects
Details
- ISSN :
- 00219606
- Volume :
- 121
- Issue :
- 18
- Database :
- OpenAIRE
- Journal :
- The Journal of chemical physics
- Accession number :
- edsair.doi.dedup.....3346deb00f050fcc18ee0a9823a28ff2