Enhanced field emission properties from two-step screen-printed carbon nano-tube film

Carbon nanotubes (CNTs) have been widely studied as a electron emitting sources of thin cold cathode. Screen printed technology has advantage of large size display, easy process and low cost, hence it attracts much more attention than other traditional method in the fabrication of CNT-FED. However, due to random distribution of CNTs in printed cathode film, poor luminance and emission uniformity have hindered the further commercial development of CNT-FED. Two-step screen-printed carbon nanotube film is presented here. CNT paste was synthesized by mixing of CNT powders, organic binders and inorganic vehicles. The prepared pastes were screen-printed on ITO glass with the printing area of 2.5 cmtimes2.5 cm, and conducted a heat treatment. Re-printed and third-printed process was conducted upon the as-printed one. Microstructure of the films was characterized via field emission scanning electronic microscopy (FESEM JEOL JSM6700F) and the OLYMPUS laser scanning confocal microscope (LEXT OLS3100). Additionally, the field emission characteristics were tested in diode structure. The vacuum level is about 5times10^-6 Torr.