Field emission from a-C:H and a-C:H:N

Parallel plate field emission measurements using a-C:H and a-C:H:N thin-film cathodes deposited at room temperature in a magnetically confined radiofrequency plasma enhanced chemical vapor deposition chamber reveal a low emission barrier of 0.05 eV. The onset fields for emission are in the 20 to 30 V/mu m range. Currents which are two orders higher were measured from the a-C:H:N films compared to a-C:H films. A current density of 0.2 mA/cm(2) (taking the entire film surface as the emitting area) at 40 V/mu m was obtained from an a-C:H:N film with 11 at.% of N. An a-C:H:N film with 15% N gave a space charge limited current density of 0.2 mA/cm(2) at 20 V/mu m.