Covalent attachment of acetonitrile on Si(100) through Si-C and Si-N linkages

The covalent binding and adsorption states of acetonitrile on Si(100) have been investigated using temperature programmed desorption (TPD), x-ray photoelectron spectroscopy (XPS), high-resolution electron energy loss spectroscopy (HREELS), and density function theory (DFT) calculation. XPS and HREELS results show that acetonitrile chemisorbs on Si(100) in a side-on di-sigma binding configuration, forming Si-C and Si-N sigma bonds. TPD measurements reveal the presence of two desorption states, beta1 and beta2 with desorption energies of 29.8 and 24.6 kcal mol-1, respectively. Based on DFT calculations, the beta1 state is possibly assigned to di-sigma bonded acetonitrile on top of a dimer and/or in an in-row bridging chemisorption, while the beta2 state is related to acetonitrile bonded in a cross-row bridging configuration. (C) 2001 American Institute of Physics.