Growth and properties of few-layer graphene prepared by chemical vapor deposition

TL;DR

This study investigates the structure and properties of few-layer graphene produced by CVD, revealing insights into its growth mechanisms and demonstrating its potential for flexible, transparent electrodes and molecular detection.

Contribution

It provides a detailed analysis of the growth mechanisms and structural properties of CVD-grown FLG, highlighting its electrical, mechanical, and optical characteristics.

Findings

FLG exhibits metallic electronic transport properties.

Young's modulus of FLG-coated polycarbonate significantly increases.

Sample suitable for flexible transparent electrodes and high-resolution molecular detection.

Abstract

The structure, and electrical, mechanical and optical properties of few-layer graphene (FLG) synthesized by chemical vapor deposition (CVD) on a Ni coated substrate were studied. Atomic resolution transmission electron microscope (TEM) images show highly crystalline single layer parts of the sample changing to multilayer domains where crystal boundaries are connected by chemical bonds. This suggests two different growth mechanisms. CVD and carbon segregation participate in the growth process and are responsible for the different structural formations found. Measurements of the electrical and mechanical properties on the centimeter scale provide evidence of a large scale structural continuity: 1) in the temperature dependence of the electrical conductivity, a non-zero value near 0 K indicates the metallic character of electronic transport; 2) the Young's modulus of a pristine polycarbonate film (1.37 GPa) improves significantly when covered with FLG (1.85 GPa). The latter indicates an extraordinary Young modulus value of the FLG-coating of TPa orders of magnitude. Raman and optical spectroscopy support the previous conclusions. The sample can be used as a flexible and transparent electrode and is suitable for special membranes to detect and study individual molecules in high resolution TEM.