Atomic-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 aβ-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.
Keywords: STM; atomic-scale manipulation; diethyl ether; organic molecules; silicon surface; tip-induced reaction.
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