FIELD-EMISSION CHARACTERISTICS OF CARBON TIPS

Field emission (FE) of glassy carbon tips is investigated. Experimental FE characteristics are as follows: (1) The decrease in FE current after flashing is very small or not recognized. (2) The FE current (about 1 micro A) is more stable than that of a tungsten tip for the same conditions as time increases. Current instabilities appear as step-wise fluctuations. (3) Instability dependences of FE current on ambient gases are in decreasing order, CO, H2O,O2 and H2. Dependence on CO is particularly remarkable. (4) FE angle is confined to 1 4- 1 5 of that of a conventional tungsten tip, and depends only on geometrical tip shape. © 1979.