Alkyl-terminated Si(111) surfaces: A high-resolution, core level photoelectron spectroscopy study

The bonding of alkyl monolayers to Si(111) surfaces has been studied with high-resolution core level photoelectron spectroscopy (PES). Two very different wet-chemical methods have been used to prepare the alkyl monolayers: (i) Olefin insertion into the H-Si bond of the H-Si(111) surface, and (ii) replacement of Cl on the Cl-Si(111) surface by an alkyl group from an alkyllithium reagent. In both cases, PES has revealed a C 1s component shifted to lower binding energy and a Si 2p component shifted to higher binding energy. Both components are attributed to the presence of a C-Si bond at the interface. Along with photoelectron diffraction data [Appl. Phys. Lett. 71, 1056, (1997)], these data are used to show that these two synthetic methods can be used to functionalize the Si(111) surface. (C) 1999 American Institute of Physics. [S0021-8979(98)00324- 7].