Formation of magic gold fingers under mild and relevant experimental conditions

Abstract

Using electrochemical scanning tunneling microscopy (EC-STM) at room temperature and under a liquid layer, magic gold fingers were grown in the presence of three different amino acids, N-Boc-L-Isoleucine, L-Tyrosine, and L-Phenylalanine. The surface was modified using a very mild electric field induced by the tip and the interaction of amino acid molecules with the Au(111) surface. When 0.28 V vs Ag/AgCl was supplied to the working electrode, an extremely small tunneling current of 0.07 nA and a bias of −0.1 V could be used to induce the surface modification. It is clear that a combination of the interaction of the molecules with the surface and the external potential led to the formation of the fingers. The results demonstrate the first instance of this surface structure formed at such mild electric field conditions and imaged under relevant experimental parameters, i.e. at room temperature and in a fluid cell.