The Atomic Drill Bit: Precision Controlled Atomic Fabrication of 2D Materials.

The ability to deterministically fabricate nanoscale architectures with atomic precision is the central goal of nanotechnology, whereby highly localized changes in the atomic structure can be exploited to control device properties at their fundamental physical limit. Here, we report on an automated, feedback-controlled atomic fabrication method and demonstrate formation of 1D-2D heterostructures in MoS 2 through selective transformations along specific crystallographic orientations. We use the atomic-scale probe of an aberration corrected scanning transmission electron microscope (STEM) and control the shape and symmetry of the scan pathway relative to the sample orientation. The focused and shaped electron beam is used to reliably create Mo 6 S 6 nanowire (MoS-NW) terminated metallic-semiconductor 1D-2D edge structures within a pristine MoS 2 monolayer with atomic precision. From these results, it is found that a triangular beam path aligned along the (zig-zag sulfur terminated) ZZS direction forms stable MoS-NW edge structures with the highest degree of fidelity without resulting in disordering of the surrounding MoS 2 monolayer. Density functional theory (DFT) calculations and ab initio molecular dynamic simulations (AIMD) are used to calculate the energetic barriers for the most stable atomic edge structures and atomic transformation pathways. These discoveries provide an automated method to improve understanding of atomic-scale transformations while opening a pathway towards more precise atomic-scale engineering of materials. This article is protected by copyright. All rights reserved.