Hydrogen chemisorption and thermal desorption on the diamond C(111) surface

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/28410

Title:	Hydrogen chemisorption and thermal desorption on the diamond C(111) surface
Authors:	Su,C;Song,KJ;Wang,YL;Lu,HL;Chuang,TJ;Lin,JC
Contributors:	中央大學
Keywords:	CHEMICAL-VAPOR-DEPOSITION;AB-INITIO CALCULATIONS;ATOMIC-HYDROGEN;INFRARED-SPECTROSCOPY;MONOHYDRIDE PHASE;100 SURFACES;ISOTHERMAL DESORPTION;NANOCRYSTAL SURFACES;VIBRATIONAL-SPECTRA;(100)2X1 SURFACE
Date:	1997
Issue Date:	2010-06-29 19:48:18 (UTC+8)
Publisher:	化學研究所
Abstract:	Temperature programmed desorption (TPD) and low energy electron diffraction (LEED) were utilized to study the interaction of atomic hydrogen with single crystal diamond C(111) surface. From isotherm and isostere analysis of TPD spectra acquired at various sample heating rates ranging from 0.6 K/s to 30 K/s, the kinetic parameters were extracted. It is found that molecular hydrogen desorption from the C(111) surface exhibits the first-order kinetics, This result is confirmed by no apparent shift in peak temperatures of TPD spectra for hydrogen coverage above 0.2 ML. At lower coverage regime, the isothermal desorption experiment also indicates the first-order desorption kinetics. A nearly coverage-independent activation energy of (3.7 +/- 0.1) eV and a prefactor of (9.5 +/- 4.0)x10(13) s(-1) are obtained except at relatively low coverages (below similar to 0.2 ML). In addition, the half-order LEED spots intensity decreases linearly with increase of the hydrogen coverage and drops to zero at similar to 0.5 ML. These results are interpreted with a model that during adsorption hydrogen atoms segregate to form metastable, highly hydrogenated domains from where hydrogen atoms recombine and desorb concertedly as the substrate surface is heated up. The comparison of this work with the hydrogen adsorption and desorption on silicon surfaces is also discussed, (C) 1997 American Institute of Physics.
Relation:	JOURNAL OF CHEMICAL PHYSICS
Appears in Collections:	[Graduate Institute of Chemistry] journal & Dissertation

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