Improved electronic and magnetic properties of reduced graphene oxide films
Nano-Scale Transport Physics Laboratory, School of Physics, University of the Witwatersrand - Private Bag 3, WITS 2050, Johannesburg, South Africa
2 DST/NRF Centre of Excellence in Strong Materials, University of the Witwatersrand - Private Bag 3, WITS 2050, Johannesburg, South Africa
3 Microsystems Center, Tyndall National Institute - Lee Maltings, Dyke Parade, Cork, Ireland
Accepted: 19 December 2011
We demonstrate semi-metallic transport in graphene oxide layers treated with an organic acid through a nearly linear current-vs.-voltage relationship and the weak temperature dependence of resistance from high temperatures down to 20 K. Additionally an energy gap was observed below 17 K due to the formation of local barriers by residual oxygen groups and disorder in reduced graphene oxide (RGO) sheets. At higher temperatures resistance shows a negative T2 temperature dependence. Temperature dependent magnetization measurements showed a phase transition from diamagnetic to ferromagnetic at around 10 K, in agreement with the electronic transport properties of the RGO films.
PACS: 81.05.U- – Carbon/carbon-based materials / 68.65.Pq – Graphene films / 72.80.Vp – Electronic transport in graphene
© EPLA, 2012