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Title: Interaction of Oxygen with TiN(001): N O Exchange and Oxidation Process

Abstract

This work presents a detailed experimental and theoretical study of the oxidation of TiN(001) using a combination of synchrotron-based photoemission and density functional theory (DFT). Experimentally, the adsorption of O{sub 2} on TiN(001) was investigated at temperatures between 250 and 450 K. At the lowest temperature, there was chemisorption of oxygen (O2,gas{yields}2Oads) without significant surface oxidation. In contrast, at 450 K the amount of O{sub 2} adsorbed increased continuously, there was no evidence for an oxygen saturation coverage, a clear signal in the Ti 2p core level spectra denoted the presence of TiO{sub x} species, and desorption of both N{sub 2} and NO was detected. The DFT calculations show that the adsorption/dissociation of O{sub 2} is highly exothermic on a TiN(001) substrate and is carried out mainly by the Ti centers. A high oxygen coverage (larger than 0.5 ML) may induce some structural reconstructions of the surface. The exchange of a surface N atom by an O adatom is a highly endothermic process ({Delta}E=2.84 eV). However, the overall oxidation of the surface layer is thermodynamically favored due to the energy released by the dissociative adsorption of O{sub 2} and the formation of N{sub 2} or NO. Both experimental and theoreticalmore » results lead to conclude that a TiN+mO{sub 2}{yields}TiO{sub x}+NO reaction is an important exit channel for nitrogen in the oxidation process.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
930540
Report Number(s):
BNL-80614-2008-JA
Journal ID: ISSN 0021-9606; JCPSA6; TRN: US200904%%578
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 126
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; TITANIUM NITRIDES; OXIDATION; PHOTOEMISSION; CHEMISORPTION; DENSITY FUNCTIONAL METHOD; DESORPTION; NITROGEN; NITRIC OXIDE; DISSOCIATION; REACTION KINETICS; national synchrotron light source

Citation Formats

Graciani,J., Fdez Sanz, J., Asaki, T., Nakamura, K., and Rodriguez, J. Interaction of Oxygen with TiN(001): N O Exchange and Oxidation Process. United States: N. p., 2007. Web. doi:10.1063/1.2743418.
Graciani,J., Fdez Sanz, J., Asaki, T., Nakamura, K., & Rodriguez, J. Interaction of Oxygen with TiN(001): N O Exchange and Oxidation Process. United States. doi:10.1063/1.2743418.
Graciani,J., Fdez Sanz, J., Asaki, T., Nakamura, K., and Rodriguez, J. Mon . "Interaction of Oxygen with TiN(001): N O Exchange and Oxidation Process". United States. doi:10.1063/1.2743418.
@article{osti_930540,
title = {Interaction of Oxygen with TiN(001): N O Exchange and Oxidation Process},
author = {Graciani,J. and Fdez Sanz, J. and Asaki, T. and Nakamura, K. and Rodriguez, J.},
abstractNote = {This work presents a detailed experimental and theoretical study of the oxidation of TiN(001) using a combination of synchrotron-based photoemission and density functional theory (DFT). Experimentally, the adsorption of O{sub 2} on TiN(001) was investigated at temperatures between 250 and 450 K. At the lowest temperature, there was chemisorption of oxygen (O2,gas{yields}2Oads) without significant surface oxidation. In contrast, at 450 K the amount of O{sub 2} adsorbed increased continuously, there was no evidence for an oxygen saturation coverage, a clear signal in the Ti 2p core level spectra denoted the presence of TiO{sub x} species, and desorption of both N{sub 2} and NO was detected. The DFT calculations show that the adsorption/dissociation of O{sub 2} is highly exothermic on a TiN(001) substrate and is carried out mainly by the Ti centers. A high oxygen coverage (larger than 0.5 ML) may induce some structural reconstructions of the surface. The exchange of a surface N atom by an O adatom is a highly endothermic process ({Delta}E=2.84 eV). However, the overall oxidation of the surface layer is thermodynamically favored due to the energy released by the dissociative adsorption of O{sub 2} and the formation of N{sub 2} or NO. Both experimental and theoretical results lead to conclude that a TiN+mO{sub 2}{yields}TiO{sub x}+NO reaction is an important exit channel for nitrogen in the oxidation process.},
doi = {10.1063/1.2743418},
journal = {Journal of Chemical Physics},
number = ,
volume = 126,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}