Silicon–Carbon Bond Inversions Driven by 60-keV Electrons in Graphene

Abstract

We demonstrate that 60-keV electron irradiation drives the diffusion of threefold-coordinated Si dopants in graphene by one lattice site at a time. First principles simulations reveal that each step is caused by an electron impact on a C atom next to the dopant. Although the atomic motion happens below our experimental time resolution, stochastic analysis of 38 such lattice jumps reveals a probability for their occurrence in a good agreement with the simulations. Conversions from three- to fourfold coordinated dopant structures and the subsequent reverse process are significantly less likely than the direct bond inversion. Our results thus provide a model of nondestructive and atomically precise structural modification and detection for two-dimensional materials.

Electronic Structure Modification of Ion Implanted Graphene: The Spectroscopic Signatures of p- and n-Type Doping

“…46,47 The differences with the present results could therefore simply be due to noise levels in previous reports, along perhaps with unintentional processing artefacts. Warner et al 43 indeed mention averaging their spectral data over several acquisitions and treating them with Principle Component analysis -see Methods section within Ref.…”

Understanding and Exploiting the Interaction of Electron Beams With Low-dimensional Materials - From Controlled Atomic-level Manipulation to Circumventing Radiation Damage

“…For Si impurities in graphene, a mechanism for a directed displacement of the impurity was identified in Ref. [4]. Based on this mechanism, we show in Fig.…”

Atom-by-Atom STEM Investigation of Defect Engineering in Graphene

“…Characterising their formation, using a far more energetic ion irradiation, is therefore essential. A combination of Raman spectroscopy and in situ electron diffraction shows that the disappearance of wrinkles in few-layer graphene sheets coincides with a progressive amorphisation of the graphene under ion irradiation [3]. High-resolution HAADF STEM imaging at 60kV reveals indeed that typical arrangements of defected carbon rings are present in samples that have been exposed to a high enough ion dose, while no such topological defect can be observed below a critical dose: fig.…”

“…1. These 'gentle' STEM observation conditions can nevertheless be used to drive the diffusion of substitutional dopants through single layer graphene, one atomic jump at a time [3]. A combined experimental and theoretical study, making use of ab initio molecular dynamic calculations, reveals that for Si dopants these jumps are not due to impact on the Si atom, but to sub-threshold impact events on the surrounding C atoms: fig.…”

“…showing a jump to a neighbouring atomic site: 6 consecutive frames from the original high frame rate movie are averaged (and filtered using a 5x5 Kuwahara filter for clarity), such that the two images presented here were effectively recorded ~0.45s apart A ball-and-stick model illustrates the atomic jump. [3] …”