Layer dependence of graphene-diamene phase transition in epitaxial and exfoliated few-layer graphene using machine learning

Abstract

The study of the nanomechanics of graphene -and other 2D materials -has led to the discovery of exciting new properties in 2D crystals, such as their remarkable in-plane stiffness and out of plane flexibility, as well as their unique frictional and wear properties at the nanoscale.Recently, nanomechanics of graphene has generated renovated interest for new findings on the pressure-induced chemical transformation of a few-layer thick epitaxial graphene into a new ultrahard carbon phase, named diamene. In this work, by means of a machine learning technique, we provide a fast and efficient tool for identification of graphene domains (areas with a defined number of layers) in epitaxial and exfoliated films, by combining data from Atomic Force Microscopy (AFM) topography and friction force microscopy (FFM). Through the analysis of the number of graphene layers and detailed Å-indentation experiments, we demonstrate that the formation of ultra-stiff diamene is exclusively found in 1-layer plus buffer layer epitaxial graphene on silicon carbide (SiC) and that an ultra-stiff phase is not observed in neither thicker epitaxial graphene (2-layer or more) nor exfoliated graphene films of any thickness on silicon oxide (SiO2).

RETRACTED: Artificial Intelligence Algorithm Enabled Industrial-Scale Graphene Characterization

“…Machine learning algorithms have also been used to identify atomic species and defects in transitioning metal chalcogenides by processing high-resolution scanning transmission electron microscopy images [20]. Combining atomic force microscopy topography and friction force microscopy characterization data, Cellini and coworkers constructed an AI clustering tool to identify domains in epitaxial and exfoliated graphene films [21].…”

Atomic force microscopy phase imaging of epitaxial graphene films

“…As displayed in figure 3(f), we consequently see an inversion of the energy dissipated by 1LG and 2LG, which is now higher for the latter, resulting from the effect of a higher indentation depth. This data is in agreement with nanoindentation measurements performed on EG [12] that proved higher contact stiffness for 1LG compared to 2LG. As the tip oscillates in hard tapping conditions, together with the transition to the repulsive regime we observe a drop in the dissipated energy.…”

“…Due to the complex growth dynamics, the graphene films generally show heterogeneous surfaces, which encompasses regions with non-uniform thicknesses and properties. Given these premises, a large scientific effort is underway to investigate the fundamental properties of EG films, using and integrating non-invasive and versatile characterization techniques to rapidly gather information from the heterogeneous surface of the studied atomic thin film [9][10][11][12].…”

Pressure‐Induced Formation and Mechanical Properties of 2D Diamond Boron Nitride

“…MoNI/Å-Indentation for Transverse Elasticity of h-BN Flakes: MoNI/Åindentation is discussed in details in Refs. [15,26,27] . For the experiments presented here, a sinusoidal voltage (<0.6 mV) applied using a lockin amplifier (Stanford Research Systems, SR830) to the piezotube of a commercial AFM (Agilent PicoPlus AFM) was used to drive small oscillations (Δz piezo ≈ 0.1 Å) in parallel to the main AFM driving voltages.…”