Low-temperature synthesis of high-quality graphene by methane plasma annealing of graphene oxide

This study explored a novel approach to synthesizing high-quality graphene on the technologically important dielectric substrates sapphire and diamond, via methane plasma annealing of graphene oxide at relatively low temperatures. High-quality graphene exhibiting a carrier mobility of 530 cm2/V s was synthesized on sapphire substrates at temperatures below 400 °C. This mobility was significantly higher than the values of approximately 5 cm2/V s obtained using conventional reduction methods. This improvement was attributed to the greatly improved quality of graphene and to the catalytic effect of the sapphire substrates, which facilitated both defect repair and graphene formation. A graphene specimen showing bipolar conductivity was also fabricated on a diamond substrate. This ability to integrate graphene with diamond could be used in novel applications such as high-performance, high-power electronic devices. The technique demonstrated herein enables the efficient, low-temperature synthesis of high-quality graphene on a diverse range of dielectric substrates, offering new opportunities for advanced electronic applications.