Scalable growth of graphene nanostructure on copper by CVD: Electrical and thermal properties for nanoelectronics

Abstract

Chemical vapor deposition on copper is still the most practical route to large-area graphene with reliable layer control and by a meaningful gap. We grew graphene nanofilms by CVD at 1000 °C under controlled methane partial pressure and measured their structural, electrical, and thermal properties on the same sample set. XRD Scherrer analysis using the equation L = Kλ/(β cosθ) (K = 0.89, λ = 0.15406 nm) applied to the (002) reflection at 2θ ≈ 26.32° gives a mean coherent stacking domain size of 8–12 nm, indicating nanoscale coherent graphitic ordering within the films. That confirms the films are nanocrystalline before any transport measurement is interpreted. Raman spectroscopy gives an I(D)/I(G) ratio below 0.05, with a well-resolved, layer-dependent 2D band across monolayer, bilayer, and trilayer regions. Electrically, conductivity reaches ~10⁵ S·m⁻¹ past the percolation threshold, with Ohmic I–V response indicating continuous inter-domain contact. Thermal conductivity drops from ~550 W·m⁻¹·K⁻¹ at 80 K to ~300 W·m⁻¹·K⁻¹ at 300 K, driven by Umklapp phonon scattering and grain-boundary suppression of phonon mean free paths. Nanoindentation on suspended regions gives an in-plane Young's modulus of ~0.85 TPa, close to the intrinsic graphene limit, which fits the low defect density the Raman spectra already showed. These results, across four independent measurement techniques on the same films, give a consistent picture of what CVD graphene actually is structurally and what that means for its use in flexible nanoelectronics and nanoscale thermal management.