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Title: Tuning patterning conditions by co-adsorption of gases: Br{sub 2} and H{sub 2} on Si(001)

We have studied the co-adsorption of Br{sub 2} and H{sub 2} on Si(001), and obtained co-adsorption energies and the surface phase diagram as a function of the chemical potential and pressure of the two gases. To do this, we have used density functional theory calculations in combination with ab initio atomistic thermodynamics. Over large ranges of bromine and hydrogen chemical potentials, the favored configuration is found to be either one with only Br atoms adsorbed on the surface, at full coverage, in a (3 × 2) pattern, or a fully H-covered surface in a (2 × 1) structure. However, we also find regions of the phase diagram where there are configurations with either only Br atoms, or Br and H atoms, arranged in a two-atom-wide checkerboard pattern with a (4 × 2) surface unit cell. Most interestingly, we find that by co-adsorbing with H{sub 2}, we bring this pattern into a region of the phase diagram corresponding to pressures that are significantly higher than those where it is observed with Br{sub 2} alone. We also find small regions of the phase diagram with several other interesting patterns.
Authors:
;  [1] ;  [2] ;  [3]
  1. Theoretical Sciences Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore - 560064 (India)
  2. SRDC-India, IBM Systems and Technology Group, Bangalore (India)
  3. IBM Systems and Technology Group, Hopewell Junction, New York 12533 (United States)
Publication Date:
OSTI Identifier:
22251448
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 139; Journal Issue: 18; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ADSORPTION; BROMINE; DENSITY FUNCTIONAL METHOD; GASES; HYDROGEN; PHASE DIAGRAMS; POTENTIALS; THERMODYNAMICS