Diamond and boron carbide field emission in medium vacuum

Field electron emission current-time and current-voltage measurements were made on single field emitters of synthetic diamond and boron carbide in medium vacuum (10(-5)-10(-8) Torr), and two diamond specimens were characterized by scanning electron microscopy (SEM) and field ion microscopy (FIM). Generally, we found that the boron carbide emitters were less noisy than the diamond emitters, and that emission current stability improved with increasing current, at least up to 6 x 10(-6) A. Use of the conventional field electron microscope (FEM) configuration enabled direct visualization of the surface condition during emission current and voltage measurements, and the combination of FIM and FEM permitted an estimation of current density for one diamond specimen, 1 X 10(6) A/cm(2). Copyright (C) 2007 John Wiley & Sons, Ltd.