Electron field emission from hydrogen-free amorphous carbon-coated ZnO tip array

Enhanced electron field emission from hydrogen-free amorphous carbon (a-C) films deposited on ZnO-tip-array-coated Si substrates was studied. Both the ZnO tip array and the a-C films were deposited by filtered are deposition. Compared with the a-C film deposited on Si substrates, the a-C film on ZnO had a lower threshold field (4.5 V/mum), higher field emission current density (0.215 mA/cm(2) at 14.3 V/mum) and higher emission site density (>2X 10(3)/cm(2) at 20 V/mum). The introduction of the ZnO tip array provides high local geometric electric-field enhancement for the a-C film. On the other hand, the amount of excess Zn in the ZnO film provides better conductivity. The result is that the electrons can be easily penetrated into the a-C films, which enhances the field emission properties. (C) 2002 American Vacuum Society.