Graphene-on-Diamond Devices with Enhanced Current-Carrying Capacity: Carbon sp2-on-sp3 Technology

摘要

Graphene demonstrated potential for practical applications owing to itsexcellent electronic and thermal properties. Typical graphene field-effecttransistors and interconnects built on conventional SiO2/Si substrates revealthe breakdown current density on the order of 1 uA/nm2 (i.e. 10^8 A/cm2) whichis ~100\times larger than the fundamental limit for the metals but stillsmaller than the maximum achieved in carbon nanotubes. We show that byreplacing SiO2 with synthetic diamond one can substantially increase thecurrent-carrying capacity of graphene to as high as ~18 uA/nm2 even at ambientconditions. Our results indicate that graphene's current-induced breakdown isthermally activated. We also found that the current carrying capacity ofgraphene can be improved not only on the single-crystal diamond substrates butalso on an inexpensive ultrananocrystalline diamond, which can be produced in aprocess compatible with a conventional Si technology. The latter was attributedto the decreased thermal resistance of the ultrananocrystalline diamond layerat elevated temperatures. The obtained results are important for graphene'sapplications in high-frequency transistors, interconnects, transparentelectrodes and can lead to the new planar sp2-on-sp3 carbon-on-carbontechnology.