Ab initio study of adsorption and decomposition of NH{sub 3} on Si(100)-(2x1)
The authors investigate the mechanism of NH{sub 3} adsorption and initial decomposition on the (2x1) reconstructed Si-(100) surface using B3LYP density functional theory. The Si(100)-(2x1) surface is described using cluster approximation. Ammonia is found to absorb on the down atom of the buckled silicon dimer with no activation barrier. The authors also find that only half of the surface silicon atoms are active sites for ammonia adsorption. Ammonia adsorption on the Si(100)-(2x1) is exothermic with an adsorption energy of 29 kcal/mol. Dissociation of the adsorbed ammonia to form NH{sub 2}(a) and H(a) proceeds with a low activation energy of 5 kcal/mol below the NH{sub 3}(g) and bare Si(100)-(2x1) energy. The calculated recombination desorption energy of 51 kcal/mol is found to be in good agreement with the temperature-programmed desorption experimental results of 47 kcal/mol. Additional, calculated vibrational spectra of NH{sub 2}(a) and H(a) agree within 2% of the experimental high-resolution electron energy loss spectra.
- Research Organization:
- Stanford Univ., CA (US)
- OSTI ID:
- 20026924
- Journal Information:
- Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical, Vol. 104, Issue 11; Other Information: PBD: 23 Mar 2000; ISSN 1089-5647
- Country of Publication:
- United States
- Language:
- English
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