Temperature dependence of the work function of hafnium islands on tungsten

Two-dimensional islands of hafnium near {100{ faces of tungsten and their terraces were examined by field electron microscopy. The two-dimensional sublimation energy of the islands was found to be 6.1±0.5 eV. The field electron emission from the islands grows with temperature, the effect being considerably greater than theoretically expected. The negative temperature coefficient of ϕ, α_T, for the islands was estimated at (4–6)×10⁻⁴ eV grad⁻¹ or more, whereas for pure tungsten α_T was found to be 2×10⁻⁵ eV grad⁻¹.