THE SURFACE-REACTIONS OF ETHYL GROUPS ON SI(100) FORMED VIA DISSOCIATION OF ADSORBED DIETHYLZINC

The adsorption and reaction of diethylzinc on S(100)-2 x 1 surfaces has been studied using temperature programmed desorption and high resolution electron energy loss spectroscopy. Adsorbed diethylzinc dissociates on the S(100)-2 x 1 surface at temperatures below 400 K to form adsorbed zinc metal and ethyl groups. The zinc metal desorbs between 400 and 550 K leaving only adsorbed ethyl groups. These ethyl groups undergo beta-hydride elimination at 550 K, producing both adsorbed and gaseous ethylene, as well as adsorbed hydrogen. The adsorbed ethylene, bound to the surface in a di-sigma configuration, is stable up to 625 K, at which point it either desorbs directly or undergoes C-C bond scission to form surface CH2 groups. For low coverages the adsorbed CH2 species undergo complete dehydrogenation while for higher coverages a fraction recombine to form gaseous ethylene at 750 K.