Enhanced field emission of vertically oriented carbon nanosheets synthesized by C2H2/H2 plasma enhanced CVD

Carbon nanosheets, free-standing, two-dimensional, carbon nanostructures with atomically thin edges, were synthesized by radio frequency plasma enhanced chemical vapor deposition. This work reports nanosheet growth using acetylene as a feedstock gas. The maximum acetylene nanosheet growth rate was found to be 16 mu m/h or similar to 8 times that of previously reported methane nanosheets. The acetylene nanosheets have a smooth surface morphology, an ordered, vertical orientation, a uniform sheet height distribution and a graphitic structure containing some defects. In emission current density vs. applied electric field (J-E) field emission measurements, the acetylene nanosheets have a threshold field, for 10 mu A/cm(2) current density, of similar to 3.0 V/mu m. In direct current emission mode, a stable continuous milliampere level emission current, corresponding to a current density up to 9.4 mA/cm(2), was collected from acetylene nanosheet samples for more than 100 h. (C) 2011 Elsevier Ltd. All rights reserved.