High-Temperature Contact Potential Difference and Thermionic Emission Analysis Using Kelvin Probe Systems

Understanding the work function of materials used in vacuum electron devices (VEDs) is an important contribution to cathode research today. This is because a lower work function material has the capability to thermionically emit high current densities at lower operating temperatures, meaning longer lifetimes for the VEDs. Two work function analysis techniques are outlined here: measurement of contact potential difference (CPD) at high temperatures and Richardson-Dushman analysis on collected current density data. Both techniques are performed using a Kelvin probe. The techniques are outlined and data collected on pure tungsten are provided.