Field emission from tetrahedral amorphous carbon as a function of surface treatment and substrate material

To understand the mechanism of electron field emission from diamond-like carbon, tetrahedral amorphous carbon (ta-C) films were subjected to Ar, H-2, and O-2 plasma treatments to change their surface condition and were deposited on substrates of different work function. The threshold fields and current densities for undoped ta-C are found to be significantly improved by the plasma treatments, largely due to an increase in emission site density, while little dependence was found on work function of substrate. This suggests that the main barrier to emission from ta-C is at the front surface. (C) 1999 American Institute of Physics. [S0003-6951(99)01811-2].