INTERACTION OF HCN (DCN) WITH SI(111)-7X7 STUDIED WITH HREELS, UPS, AND XPS

The interaction of HCN (DCN) with Si(111)-7x7 was studied with high-re solution electron energy loss spectroscopy (HREELS), ultraviolet photo electron spectroscopy (UPS), and X-ray photoelectron spectroscopy (XPS ). HCN (DCN) formed dimers and/or polymers on the surface at 100 K wit h higher dosages (D > 4 langmuirs). Above 200 K, CN radicals in an end -on adsorption geometry were identified as the major species which sur vived up to 600 K on the surface. This observation was different from that with HCN (DCN) on Si(100)-2x1, where the relative concentration o f the HCNH species was higher. The observed difference in the behavior of HCN (DCN) on Si(111)-7x7 and Si(100)-2x1 could be ascribed to the different topologies of the two surfaces.