Site-selective substitutional doping with atomic precision on stepped Al (111) surface by single-atom manipulation
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NANO EXPRESS
Open Access
Site-selective substitutional doping with atomic precision on stepped Al (111) surface by single-atom manipulation Chang Chen1, Jinhu Zhang1, Guofeng Dong1, Hezhu Shao1, Bo-yuan Ning1, Li Zhao2, Xi-jing Ning3 and Jun Zhuang1*
Abstract In fabrication of nano- and quantum devices, it is sometimes critical to position individual dopants at certain sites precisely to obtain the specific or enhanced functionalities. With first-principles simulations, we propose a method for substitutional doping of individual atom at a certain position on a stepped metal surface by single-atom manipulation. A selected atom at the step of Al (111) surface could be extracted vertically with an Al trimer-apex tip, and then the dopant atom will be positioned to this site. The details of the entire process including potential energy curves are given, which suggests the reliability of the proposed single-atom doping method. Keywords: Single-atom doping; Substitutional; Single-atom manipulation; Atomic precision; Metal surface
Background Single-atom manipulation, which was first introduced by Eigler et al. and realized experimentally on Ni (111) surface with a scanning tunneling microscope (STM) tip, provides a way to fabricate nanostructures with atomic precision [1-7]. Besides the STM tip, for nonconductive surface, the tip of an atomic force microscope (AFM) has also been applied to achieve various single-atom manipulations [8-10]. Studies show that merely by the mechanical interaction force acting between the tip and atom, complex manipulations can still be accomplished besides the primary lateral and vertical manipulations. For instance, on Al (111) surface, a reversible modification of the configuration of supported nanoclusters with atomic precision by tip was demonstrated in our previous simulations [11]. Also, the work on Si (111) surface given by Sugimoto et al. shows that an atom from the AFM tip can interchange with a surface adatom in a reversible exchange procedure [9]. Through this vertical manipulation, a single Si atom can be precisely positioned into or extracted from the Sn layer. As the size of * Correspondence: [email protected] 1 Shanghai Engineering Research Center of Ultra-Precision Optical Manufacturing, Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China Full list of author information is available at the end of the article
devices shrinks to nanoscale or even to atomic scale, besides configuration of nanostructure, the number of isolated atoms of certain species and their location could modify their functionality and performance [12,13]. Therefore, it is sometimes demanded to position dopants at certain sites precisely. For example, by STM-based hydrogen lithography, a single-atom transistor in which an individual P dopant atom has been placed within a silicon device with a spatial accuracy of one lattice site was demonstrated recently [14]. In another work, by Cs atom doping with a STM tip, spin of individual magnetic molecules as basis of quantu
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