Coulomb sink effect on coarsening of metal nanostructures on surfaces

Abstract

We discuss Coulomb effects on the coarsening of metal nanostructures on surfaces. We have proposed a new concept of a “Coulomb sink” [Phys. Rev. Lett., 2004, 93: 106102] to elucidate the effect of Coulomb charging on the coarsening of metal mesas grown on semiconductor surfaces. A charged mesa, due to its reduced chemical potential, acts as a Coulomb sink and grows at the expense of neighboring neutral mesas. The Coulomb sink provides a potentially useful method for the controlled fabrication of metal nanostructures. In this article, we will describe in detail the proposed physical models, which can explain qualitatively the most salient features of coarsening of charged Pb mesas on the Si(111) surface, as observed by scanning tunneling microscopy (STM). We will also describe a method of precisely fabricating large-scale nanocrystals with well-defined shape and size. By using the Coulomb sink effect, the artificial center-full-hollowed or half-hollowed nanowells can be created.

Keywords

Coulomb sink, metal nanostructures, coarsening, STM