Field emission from the film of the finely dispersed arc discharge black core material

We have studied, for the first time, the field emission from the film, prepared by a spray method, of the finely dispersed black core material, including multi-walled carbon nanotubes (MWNTs), fabricated by arc discharge. We dispersed the black core material by using an ultrasonic processor and found that the dispersed ones were much finer than those observed when treated with a ball mill and normal ultra-sonic bath. By SEM, HRTEM and Raman analyses, the MWNTs were almost not deformed and damaged during ultra-sonication. The field emission current density measured from the film of the dispersed black core material was about 15 mA/cm2 at an applied field of 8 V/μm, which was about 23 times higher than that found by a ball mill. A current density of 1 mA/cm2, which is required basically for flat panel display, has been obtained at 5.3 V/μm. The lifetime test of the dispersed black core material showed that the current density was almost unchanged while the field was applied. Therefore, it is concluded that a black core material fabricated by arc discharge could be used to flat panel displays as field emitters by dispersing with an ultrasonic processor, without further treatment like extraction or purification.