ScholarWorks@숙명여자대학교

초록

Adsorption of CO molecules on Si(111)-(7x7) is investigated by using scanning tunneling microscopy (STM) and density-functional theory calculations. The most reactive site on the Si(111)-(7x7) surface is the corner adatom in the faulted half unit (FHU), followed by the center adatom in the FHU. The initial sticking probability of CO molecules on Si(111)-(7x7) at room temperature (RT) is estimated to be similar to 4 x 10(10) molecules/(cm(2). Langmuir), which is comparable with that on Si(001)-(2x1). From the experiments and theoretical calculations, the adsorption of CO molecules are found to occur on Si adatoms either in the upright on-top configuration or in the back-bond inserted configuration, while the adsorption on the rest and the corner hole atoms (which are theoretically probable) are not observable using STM due to their low-lying geometries. Though the sticking probability is very low, every surface dangling bond on the surface can bind strongly with the C atom of a CO molecule even at temperatures higher than RT.

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