Growth Mechanism for Low Temperature PVD Graphene Synthesis on Copper Using Amorphous Carbon

Udit Narula,Cher Ming Tan,Chao Sung Lai

doi:10.1038/srep44112

Abstract

Growth mechanism for synthesizing PVD based Graphene using Amorphous Carbon, catalyzed by Copper is investigated in this work. Different experiments with respect to Amorphous Carbon film thickness, annealing time and temperature are performed for the investigation. Copper film stress and its effect on hydrogen diffusion through the film grain boundaries are found to be the key factors for the growth mechanism, and supported by our Finite Element Modeling. Low temperature growth of Graphene is achieved and the proposed growth mechanism is found to remain valid at low temperatures.

Highlights

Growth of Graphene on Copper using CVD has been demonstrated by Li et al.[11,12] and others[13,14]
In view of the limitation of the reported methods, the use of amorphous carbon as solid source for Graphene synthesis on Cu was re-explored by Ji et al.[21]
Based on the results obtained in this work, we propose the plausible mechanism for the Graphene synthesis using amorphous carbon as the solid carbon source in presence of copper catalyst as depicted in Fig. 8 which consists of four steps

Summary

Introduction

Growth of Graphene on Copper using CVD has been demonstrated by Li et al.[11,12] and others[13,14]. A simpler and low cost technique to obtain non-transferable Graphene using amorphous carbon as solid source and Nickel or Cobalt thin film as catalyst annealed at elevated temperatures has been reported[15,16,17] This technique can be instrumental in controlling the number of Graphene layers, eliminates the need for Graphene transfer and is economical as it uses amorphous carbon as the carbon source. The transfer of Graphene introduces many structural inhomogeneities which causes degradation of properties of graphene such as the mobility, electrical and thermal conductivity etc[18,19,20] Such Graphene synthesis method was reported to be not possible with Copper due to the very low solubility of Carbon in Copper[16,17]. The Graphene is in direct contact with amorphous carbon in the method used by Ji et al.[21], as the amorphous carbon layer atop Cu crystallizes to Graphene and this might result in crystal contaminations

Methods

Results

Conclusion