Thermionic work function of LaB6 single crystals and their surfaces

Abstract

The thermionic work functions and the Richardson constants for LaB₆ single crystals have been measured using a diode system with a guard ring under stable thermionic conditions. They are 2.86±0.03 eV, 82 A/cm² K² for the (100) plane, 2.68±0.03 eV, 57 A/cm² K² for the (110) plane, and 3.4±0.2 eV, 71 A/cm² K² for the (111) plane. The (111) faceting on the (110) plane has an important effect on the reduction of the thermionic current from the (110) plane at 5×10⁻⁶ Torr.