Electron field emission properties of as-deposited and nitrogen implanted tetrahedral amorphous carbon films

Tetrahedral amorphous carbon (ta-C) films have been prepared at ambient tem perature by filtered are deposition (FAD). Electron field emission properti es of the ta-C films were studied using a parallel plate diode configuratio n. Research indicated that a threshold electric field of about 16 V/mum is required to initiate the electron emission from the as-grown ta-C film. An emission current of similar to 20 muA was detected at an electric field of around 20 V/mum, following the Fowler-Nordheim (FN) field emission behavior . In order to investigate the effect of nitrogen on the field emission of t a-C, nitrogen ions were implanted into the ta-C films at an ion energy of 6 keV with ion dose varying from 1.7 to 20 x 10(15) atoms/cm(2). It was foun d that the emission current and the threshold electric field are in close r elationship with the ion dose. At the highest ion dose, the emission curren t increases to similar to 80 muA. Correspondingly, the threshold electric f ield decreases from 16.7 to 14 V/mum. The FN behavior was also observed for the nitrogen implanted ta-C films. However, the degradation of the field e mission properties is found when a lower dose of nitrogen is implanted into the films. The mechanism for the modification of field emission properties by nitrogen implantation is discussed. (C) 2001 Elsevier Science B.V. All rights reserved.