Adsorption and thermal reaction of short-chain alkanethiols on GaAs(1 0 0)

T. P. Huang, T. H. Lin, T. F. Teng, Y. H. Lai, Wei-Hsiu Hung

Research output: Contribution to journalArticle

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Abstract

By means of temperature-programmed desorption (TPD) and X-ray photoemission spectroscopy (XPS) with synchrotron radiation, we investigated the adsorption and thermal decomposition of alkanethiols (RSH, R = CH3, C2H5, and C4H9) on a GaAs(1 0 0) surface. All chemisorbed alkanethiols can deprotonate to form thiolates below 300 K via dissociation of the sulfhydryl hydrogen (-SH). Two types of thiolates species are observed on GaAs(1 0 0), according to adsorption on surface Ga and As sites. The thiolates adsorbed on a Ga site preferentially recombine with surface hydrogen to desorb as a molecular thiol at 350-385 K. The thiolate on the As site exhibits greater thermal stability and undergoes mainly dissociation of the C-S bond at ∼520 K, independent of the alkyl chain length. The decomposition of CH3S either directly desorbs CH3 or transfers the CH3 moiety onto the surface. The surface CH3 further evolves directly from the surface at 665 K. The dissociations of C2H5S and C4H9S yield surface C2H5 and C4H9, which further decompose to desorb C2H4 and C4H8, respectively, via β-hydride elimination. The complete decomposition of alkanethiol leads to the formation of surface S without deposition of carbon. Adsorption of CH3SSCH3 results in the formation of surface CH3S at initial exposures via scission of the S-S bond. Compared with the adsorption of CH3SH, the CH3S on the Ga site exhibits greater thermal stability because surface hydrogen is absent. At a high exposure, CH3SSCH3 can absorb molecularly on the surface and decompose to desorb CH3SCH3 via formation of a CH3SS intermediate.

Original languageEnglish
Pages (from-to)1244-1252
Number of pages9
JournalSurface Science
Volume603
Issue number9
DOIs
Publication statusPublished - 2009 May 1

Fingerprint

Adsorption
adsorption
Hydrogen
dissociation
decomposition
Thermodynamic stability
Hot Temperature
gallium arsenide
thermal stability
hydrogen
Decomposition
Temperature programmed desorption
Photoelectron spectroscopy
X ray spectroscopy
Synchrotron radiation
Chain length
Sulfhydryl Compounds
thiols
Hydrides
hydrides

Keywords

  • Butanethiol
  • Dimethyl disulfide
  • Ethanethiol
  • GaAs
  • Methanethiol
  • Synchrotron radiation
  • TPD
  • XPS

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

Adsorption and thermal reaction of short-chain alkanethiols on GaAs(1 0 0). / Huang, T. P.; Lin, T. H.; Teng, T. F.; Lai, Y. H.; Hung, Wei-Hsiu.

In: Surface Science, Vol. 603, No. 9, 01.05.2009, p. 1244-1252.

Research output: Contribution to journalArticle

Huang, T. P. ; Lin, T. H. ; Teng, T. F. ; Lai, Y. H. ; Hung, Wei-Hsiu. / Adsorption and thermal reaction of short-chain alkanethiols on GaAs(1 0 0). In: Surface Science. 2009 ; Vol. 603, No. 9. pp. 1244-1252.
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T1 - Adsorption and thermal reaction of short-chain alkanethiols on GaAs(1 0 0)

AU - Huang, T. P.

AU - Lin, T. H.

AU - Teng, T. F.

AU - Lai, Y. H.

AU - Hung, Wei-Hsiu

PY - 2009/5/1

Y1 - 2009/5/1

N2 - By means of temperature-programmed desorption (TPD) and X-ray photoemission spectroscopy (XPS) with synchrotron radiation, we investigated the adsorption and thermal decomposition of alkanethiols (RSH, R = CH3, C2H5, and C4H9) on a GaAs(1 0 0) surface. All chemisorbed alkanethiols can deprotonate to form thiolates below 300 K via dissociation of the sulfhydryl hydrogen (-SH). Two types of thiolates species are observed on GaAs(1 0 0), according to adsorption on surface Ga and As sites. The thiolates adsorbed on a Ga site preferentially recombine with surface hydrogen to desorb as a molecular thiol at 350-385 K. The thiolate on the As site exhibits greater thermal stability and undergoes mainly dissociation of the C-S bond at ∼520 K, independent of the alkyl chain length. The decomposition of CH3S either directly desorbs CH3 or transfers the CH3 moiety onto the surface. The surface CH3 further evolves directly from the surface at 665 K. The dissociations of C2H5S and C4H9S yield surface C2H5 and C4H9, which further decompose to desorb C2H4 and C4H8, respectively, via β-hydride elimination. The complete decomposition of alkanethiol leads to the formation of surface S without deposition of carbon. Adsorption of CH3SSCH3 results in the formation of surface CH3S at initial exposures via scission of the S-S bond. Compared with the adsorption of CH3SH, the CH3S on the Ga site exhibits greater thermal stability because surface hydrogen is absent. At a high exposure, CH3SSCH3 can absorb molecularly on the surface and decompose to desorb CH3SCH3 via formation of a CH3SS intermediate.

AB - By means of temperature-programmed desorption (TPD) and X-ray photoemission spectroscopy (XPS) with synchrotron radiation, we investigated the adsorption and thermal decomposition of alkanethiols (RSH, R = CH3, C2H5, and C4H9) on a GaAs(1 0 0) surface. All chemisorbed alkanethiols can deprotonate to form thiolates below 300 K via dissociation of the sulfhydryl hydrogen (-SH). Two types of thiolates species are observed on GaAs(1 0 0), according to adsorption on surface Ga and As sites. The thiolates adsorbed on a Ga site preferentially recombine with surface hydrogen to desorb as a molecular thiol at 350-385 K. The thiolate on the As site exhibits greater thermal stability and undergoes mainly dissociation of the C-S bond at ∼520 K, independent of the alkyl chain length. The decomposition of CH3S either directly desorbs CH3 or transfers the CH3 moiety onto the surface. The surface CH3 further evolves directly from the surface at 665 K. The dissociations of C2H5S and C4H9S yield surface C2H5 and C4H9, which further decompose to desorb C2H4 and C4H8, respectively, via β-hydride elimination. The complete decomposition of alkanethiol leads to the formation of surface S without deposition of carbon. Adsorption of CH3SSCH3 results in the formation of surface CH3S at initial exposures via scission of the S-S bond. Compared with the adsorption of CH3SH, the CH3S on the Ga site exhibits greater thermal stability because surface hydrogen is absent. At a high exposure, CH3SSCH3 can absorb molecularly on the surface and decompose to desorb CH3SCH3 via formation of a CH3SS intermediate.

KW - Butanethiol

KW - Dimethyl disulfide

KW - Ethanethiol

KW - GaAs

KW - Methanethiol

KW - Synchrotron radiation

KW - TPD

KW - XPS

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U2 - 10.1016/j.susc.2009.03.011

DO - 10.1016/j.susc.2009.03.011

M3 - Article

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VL - 603

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JO - Surface Science

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