Formation of few-layer graphene flake structures from graphite particles during thin film coating using dry spray deposition method

This work demonstrates the formation of few-layer graphene flake structures directly from graphite particles. A nano-particle deposition system, which is a dry spray deposition method generally used for deposition of metals and ceramics, has been introduced to deposit graphite particles at room temperature. In this study, graphite powder was deposited on a Cu substrate without using binders and the deposited thin film was characterized. The deposited thin film contained few-layer graphene flake structures, as observed using field effect scanning electron microscopy and confirmed using X-ray diffraction, Raman spectroscopy and field emission transmission electron microscopy. We also suggested the critical impact velocity for deposition of few-layer graphene flake structured thin film and a mechanism for forming few-layer graphene flake structures during thin film preparation. The suggested mechanism was interlayer separation of micron-sized graphite particles and fragmentation of particles into small pieces during deposition due to the impact of graphite particles on the substrate. (C) 2016 Elsevier B.V. All rights reserved.