Tip-induced β -hydrogen dissociation in an alkyl group bound on Si(001)

AbstractAtomic-scale chemical modification of surface-adsorbed ethyl groups on Si(001) was induced and studied by means of scanning tunneling microscopy. Tunneling at sample bias >+1.5 V leads to tip-induced C–H cleavage of a β-hydrogen of the covalently bound ethyl configuration. The reaction is characterized by the formation of an additional Si–H and a Si–C bond. The reaction probability shows a linear dependence on the tunneling current at 300 K; the reaction is largely suppressed at 50 K. The observed tip-induced surface reaction at room temperature is thus attributed to a one-electron excitation in combination with thermal activation.