1 Department of Materials Science and Engineering, Chiao Tung University, 1001 University Road, Hsinchiu 30010 2 Department of Electrical Engineering, Central University, Chung-Li City, Taoyuan 32001 3 Department of Electronics Engineering and Institute of Electronics, Chiao Tung University, 1001 University Road, Hsinchiu 30010
Keywords:graphene, breakdown, high current density, in-situ transmission electron microscope (TEM), Ostwald ripening
Graphene has demonstrated its potential in several practical applications owing
to its remarkable electronic and physical properties. In this study, we successfully
fabricated a suspended graphene device with a width down to 20 nm. The
morphological evolution of graphene under various electric field effects was
systematically examined using an in-situ transmission electron microscope
(TEM). The hourglass-shaped graphene sample instantly broke apart at 7.5 mA,
indicating an impressive breakdown current density. The current-carrying capacity
was calculated to be ~1.6 × 109 A·cm–2, which is several orders higher than that of
copper. The current-carrying capacity depended on the resistivity of graphene.
In addition, atomic volume changes occurred in the multilayer graphene samples
due to surface diffusion and Ostwald ripening (OR), indicating that the breakdown
mechanism is well approximated by the electric field. This study not only provides
a theory to explain the breakdown behavior but also presents the effects on
materials contacted with a graphene layer used as the transmission path.