Field emission studies of the lanthanum hexaboride/tungsten system

Tungsten deposited with lanthanum hexaboride (LaB 6 ) is of interest, as LaB 6 is characterized by the properties of an excellent electron emitter. The authors report a field emission study of the LaB 6 /tungsten system prepared by depositing LaB 6 in situ on to a tungsten tip. The observed maximum decrease in the average work-function was from 4.52 eV (clean tungsten) to 1.75 eV (LaB 6 deposited on tungsten). The field emission pattern of tungsten deposited with LaB 6 shows preferential adsorption around the (111) and (100) planes.