Direct-Writing Atom-by-Atom

TL;DR

This paper introduces a novel electron beam direct-write process in a transmission electron microscope, using elemental tin and defect engineering in graphene for atom-by-atom material deposition.

Contribution

It demonstrates a new mechanism for direct-write deposition that involves defect creation and atomic migration, differing from traditional gas-phase precursor methods.

Findings

Successful atom-by-atom deposition on graphene

Use of temperature control to facilitate atom migration

Distinct mechanism from conventional electron beam induced deposition

Abstract

Direct-write processes enable the alteration or deposition of materials in a continuous, directable, sequential fashion. In this work we demonstrate an electron beam direct-write process in an aberration-corrected scanning transmission electron microscope. This process has several fundamental differences from conventional electron beam induced deposition techniques, where the electron beam dissociates precursor gases into chemically reactive products that bond to a substrate. Here, we use elemental tin (Sn) as a precursor and employ a different mechanism to facilitate deposition. The atomic-sized electron beam is used to generate chemically reactive point defects at desired locations in a graphene substrate. Temperature control of the sample is used to enable the precursor atoms to migrate across the surface and bond to the defect sites thereby enabling atom-by-atom direct-writing.