Field emission characteristics of lanthanum hexaboride coated silicon field emitters

Abstract

Lanthanum hexaboride(LaB6) films have been deposited on silicon tip field emitters by electron-beam evaporation. The field emission characteristics are studied in a diode test cell in a vacuum system. The experimental results show that the field emission stability of the LaB6-coated Si-tip FEA can be improved and the emission current is significantly enhanced to 75 µA, in contrast to pure Si-tip FEA of 500 nA and Mo-coated Si-tip FEA of 300 nA with 1500 V applied to the anode. Furthermore, even at low vacuum (>1.5 × 10−5 Torr) it still exhibits good emission properties and strong ability to withstand ion bombardment. This LaB6-coated Si-tip FEA is an excellent electronic candidate, in particular a fit for travelling-wave tubes, klystrons and other large vacuum apparatus.