Changes in Electrical Properties of Graphite Coatings Annealed in Air and Nitrogen Environments

Graphite has fascinated researchers since its discovery because of its unique features and potential applications. Graphite can be applied as a coating onto other materials to tailor their functionality for specific device applications. In the present study, graphite spray was deposited onto glass substrates and then annealed in air and in a N2 gas environment at different temperatures (50 °C to 500 °C). SEM, Raman, and XRD characterization techniques were employed. SEM showed the deposited graphite material has flake-like structures. Raman spectra reveal three prominent spectral bands at ~1350.91 cm−1, ~1579.19 cm−1 and ~2691.47 cm−1, which signify the G, D, and 2D vibrational modes of graphite, respectively. XRD results show three signature peaks of hexagonal graphene sheets at 2θ ≈ 26.4, 54.3, and 77.7 deg corresponding to (002), (004), and (110), respectively. Electrical conductivity of the films was investigated with the use of two- and four-probe methods. In a N2 gas environment, the annealing temperature did not have much effect on crystallinity, while significant changes in the conductivity of the graphite coatings were observed using different annealing temperatures.