The Field Emission Energy Distribution (FEED) study of electron interactions in tungsten

Abstract

Field Emission Energy Distributions (FEED) have been measured along the [001], [016] and [013] directions of a tungsten crystal within the temperature range 78 < T < 950 K. Both electron-phonon interactions and band structure effects have been considered as a function of the crystallographic orientation. Measurements over a wide range of temperature have been interpreted in terms of both electron-d hole and electron-phonon interactions. The comparison of measurements along [001], i.e. the emission mainly from the d band with those previously published along [012], i.e. the emission mainly from the s band, is consistent with the postulated s → d transitions directly. Under conditions in which electron-phonon scattering occurs, the relation of FEED to the Nottingham effect has been investigated. In the light of electron transport phenomena in tungsten the calculation of the inversion temperature seems to require a new theoretical procedure.