Controlled fabrication of freestanding monolayer SiC by electron irradiation

TL;DR

This paper introduces a precise method for fabricating freestanding monolayer SiC within graphene nanopores using electron irradiation and in-situ heating, revealing insights into atom-by-atom self-assembly of 2D materials.

Contribution

It presents a novel electron irradiation technique to control the growth of monolayer SiC within graphene nanopores with atomic precision.

Findings

Controlled patterning of nanopores and SiC growth achieved

Seamless integration of SiC with graphene lattice demonstrated

Insights into atom-by-atom self-assembly of 2D monolayers uncovered

Abstract

The design and preparation of novel quantum materials with atomic precision are crucial for exploring new physics and for device applications. Electron irradiation has demonstrated as an effective method for preparing novel quantum materials and quantum structures that could be challenging to obtain otherwise. It features the advantages of precise control over the patterning of such new materials and their integration with other materials with different functionalities. Here, we present a new strategy for fabricating freestanding monolayer SiC within nanopores of a graphene membrane. By regulating the energy of the incident electron beam and the in-situ heating temperature in a scanning transmission electron microscope (STEM), we can effectively control the patterning of nanopores and subsequent growth of monolayer SiC within the graphene lattice. The resultant SiC monolayers seamlessly connect with the graphene lattice, forming a planar structure distinct by a wide direct bandgap. Our in-situ STEM observations further uncover that the growth of monolayer SiC within the graphene nanopore is driven by a combination of bond rotation and atom extrusion, providing new insights into the atom-by-atom self-assembly of freestanding two-dimensional (2D) monolayers.