Molecular-hydrogen interaction with beta-SiC(100)3X2 and c(4X2) surfaces and with Si atomic - art. no. 201305

We investigate molecular H-2 interaction with beta -SiC(100)3x2 and beta -S iC(100) c(4x2) surfaces and with Si atomic lines by atom-resolved scanning tunneling microscopy and ultraviolet photoemission spectroscopy. While the 3x2 surface reconstruction remains totally inert, the c(4x2) is highly reac tive to H-2 with sticking probabilities up to eight orders of magnitude hig her than fur Si(100)2x1. H-2 is initially dissociated at up-dimer adsorptio n sites influencing the two neighbor down dimers. At higher exposures, hydr ogen induces a 2x1 surface transformation. This very high reactivity differ ence between 3x2 and c(4x2) reconstructions allows nonreacted Si atomic lin es formation on a hydrogenated surface.