Basic field emission properties of TiC and ZrC single crystals

Field emission characteristics concerning single crystal tips of TiC and ZrC have been studied. Experimental finding are as follows: 1) Step and spike like instabilities are observed in the field emission current from the TiC tip at room temperature. The level of the instability is increased both with increasing current level and with increasing ambient gas pressure. 2) On the other hand, a random noise is observed in the field emission current from the ZrC tip. The level of the random noise is lower than from W tip. 3) Oxidizing the tip surface reduces the work function, and hence it makes possible to obtain the larger current at lower voltages. (author)