Influence of nanocrystalline structure on work function of tungsten

Nanocrystalline structure with average grain size about 100 nm is processed in specimens of tungsten by severe plastic deformation. The microstructure is studied by ion and transmission electron microscopy. Spectra for probing area containing grain boundary has an additional peak. In the case of areas away from the grain boundary the electron energy distribution are similar to the classical one and expected from the Fowler-Nordheim theory. The work function is determined by electron-beam measurement of the contact potential difference. It has been revealed that the formation of a nanocrystalline structure results in a decrease in the electron work function of a metal. For tungsten with a grain size of about 100 nm, this decrease is equal to 0.8 V