TEMPERATURE COEFFICIENTS OF WORK FUNCTIONS OF (110) AND (100) SURFACES OF TUNGSTEN SINGLE CRYSTALS AND OF POLYCRYSTALLINE TUNGSTEN FOIL

A modification of the Kelvin contact potential difference technique has been used to measure the temperature coefficient of the work function of three tungsten surfaces over the temperature range from 77°-1300°K. Two of the surfaces were polished and etched single-crystal planes having the (110) and (100) orientations, the third was a sample of polycrystalline foil. The results obtained were foil (11±1)×10-5 eV/°K (110) (6.3±0.6)×10-5 eV/°K (100) (9.1±0.4)×10-5 eV/°K and these are in qualitative agreement with predictions based on the temperature dependence of the electron smoothing component of the surface double layer. © 1969 The American Institute of Physics.