화학공학소재연구정보센터
Journal of Vacuum Science & Technology B, Vol.23, No.2, 676-679, 2005
Field emission from teepee-shaped carbon nanotube bundles
Randomly, but perpendicular to the surface, oriented carbon nanotubes of about 5 mu m in height and submicrometer spacing were coated with 3.5 mu m plasma enhanced CVD silicon dioxide. Subsequent removal of the oxide in buffered HF, followed by de-ionized water rinse and nitrogen blow drying resulted in the formation of a peculiar pattern of nanotubes similar in shape to teepees or the hair cells of the inner ear. Since several nanotubes can supply current to the apexes of these bundles and since the spacing between the apexes is increased, thus reducing the electrostatic screening effect, these structures might have interesting field emission properties. Field emission measurements were performed at pressures of about 1 X 10(-8) Torr. Room temperature emission was poor with turn-on fields of about 30 V/mu m due to surface contamination effects. Turn-on fields of about 15 V/mu m and macroscopic current densities of 50 mA/cm(2) were obtained when the measurements were performed at 170 degrees C. (c) 2005 American Vacuum Society.