Selective functionalization of the Si(100) surface by switching the adsorption linkage of a bifunctional organic molecule

Selective functionalization by switching the adsorption linkage of a bi-functional organic molecule, 1-dimethylamino-2-propyne (DMAP), on Si(1 0 0) has been studied using high-resolution electron energy loss spectroscopy (HREELS) and scanning tunneling microscopy (STM). The HREELS and STM results clearly indicate that DMAP adsorbs at the down dimer atom of Si(1 0 0)c(4 × 2) through an N → Si dative bond leaving the –CCH unit of DMAP free at low temperature (65–90 K). The adsorption linkage is switching from the N → Si dative bond to the Si–C di-σ bonds by annealing the adsorbed surface to 300 K, and thus the tertiary amino group becomes free.