Local electron field emission characteristics of pulsed laser deposited diamondlike carbon films

Local electron field emission properties of diamondlike carbon (DLC) films were measured by a probe method in 1 atmosphere ambient pressure, using the modified scanning tunneling microscopic (STM) system, and the diode method. In the STM probe method, the field emission was turn on at a low bias as +2.67 V. A large emission current of 40 nA was attained at +7 volt bias voltage and the emission current density was estimated as J(t)=5 A/cm(2). By contrast, the current-voltage (I-V) characteristics of the same DLC films measured by diode method in 10(-6) Torr ambient pressure revealed that the electron field emission was produced for a 13.2 V mu m electric field, and a high emission current density of J=160 mu A/cm(2) was obtained for a E=20 V/mu m electric field. The geometrical enhancement factor (alpha), evaluated from the Fowler-Nordheim plot was around alpha=30, which is larger than what would be expected from a planar surface. This can be interpreted as the evidence that electrons are emitted locally from spherical SP3 clusters. (C) 1996 American Institute of Physics.