Electron emission from chemical vapor deposited diamond and amorphous carbon films observed with a simple field emission device

Electron emission from chemical vapor deposited (CVD) diamond and amorphous carbon (a-C) films was observed with a simple field emission device (FED). Both diamond and a-C films were prepared with microwave plasma-enhanced CVD techniques. Electron emission in the ficld strength range + 10 to −10 MVm⁻¹ was studied, and the field emission source was confirmed by a diode characteristic of the I-V curve, a straight line in the Fowler-Nordheim (F-N) plot, and direct observation of light emission from a fluorescent screen. The turn-on field strength was ∼5 MVm⁻¹, which was similar for both kinds of carbon films. The highest current density for diamond films, observed at a field strength of 10 MVm⁻¹, was ∼15 μA cm⁻². Diamond films yielded a higher emission current than a-C films. The reasons for the observed field emission are discussed.