Distribution of Crystal Orientation and Work Function in Tungsten Ribbons

Abstract

Polycrystalline tungsten ribbons tend to recrystallize on extended outgassing to a preferred orientation near the $\text{〈1̄10〉}$ zonal axis between the $\text{〈001〉}$ to $\text{〈112〉}$ directions, the most probable orientations being in the $\text{〈115〉}$ to $\text{〈113〉}$ directions. Work function measurements on nine different crystal planes between the $\text{〈001〉}$ to $\text{〈112〉}$ directions have been made and show variations from 4.34 to 4.72 eV. The area average value from 15 different ribbons is 4.46 eV but the variation between ribbons can be as high as 0.2 eV.