Improved electron field emission characteristics of MIM cold cathode by thin amorphous carbon film coating

Summary form only given. Due to the negative or low electron affinity of carbon materials such as amorphous carbon (a-C) and diamond thin films, they are often considered as one of the excellent candidates for field emission cathodes. Besides low electron affinity, a-C and a-CN thin films have been revealed that they are low work function (⩽2 eV) materials. In this study, we have tested a-C thin films on Metal-Insulator-Metal (MIM) cold cathodes to improve electron emission efficiency (η). a-C thin films are deposited on MIM (Al-Al/sub 2/O/sub 3/-Au) cold cathodes using simple magnetron sputtering of graphite target. The physical properties of a-C films are analyzed through Raman, UV-Visible, and Auger spectrometry. We have also evaluated the electron emission properties by current-voltage (I-V) and light emission analysis. Marked improvement has been achieved by coating thin a-C film on top of the MIM (Al-Al2O3-Au) cold cathode; the values of η obtained from surface modified MIM cathodes by a-C films are strongly dependent on the thickness of a-C as expected from the simple flat band model. These results are interpreted as the effect of surface work function lowering.