Effect of Microimpurities on the Electronic Structure and Emission Properties of Microwave Device Cathode Materials

Abstract

The effect of microimpurities on the electronic structure of barium oxide has been studied using optical and electron spectroscopy. As was shown previously, oxygen vacancies play a decisive role in the formation of the emission properties of barium oxide crystallites; however, the possible role of microimpurities in barium oxide crystallites was not considered. It has been established that some microimpurities, including nickel, scandium, and combination of calcium and strontium, order oxygen vacancies in barium oxide crystallites, which directly affects oxygen diffusion in them. Nickel and scandium impurities form additional surface states near the edge of the valence band, which is accompanied by a decrease in the electronic work function of a cathode material.