Adsorption and thermal decomposition of H2S on Si(100)-2×1 are studied by means of temperature-programmed desorption (TPD) and X-ray photoemission spectroscopy (XPS) with synchrotron radiation. The H2S molecule dissociates to form H and HS on the Si surface at adsorption temperature of 115 K. The Si(100)-2×1 surface structure is conserved upon the adsorption of H2S due to bonding of dissociative H and HS on two Si atoms in a dimer without breaking the Si-Si dimer bond. H2 and SiS are the only desorption products of thermal decomposition of H2S with peaks at 780 and 820 K, respectively. On the basis of TPD and XPS results, intermediates involved in decomposition of H2S and their adsorption configurations are proposed and discussed.
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