Correlation of field emission flicker noise and work function for tungsten single crystal planes with adsorbed potassium

The flcker noise power of the (112), (110), (100), (111) and (122) planes as well of (110) vicinals of a tungsten field emitter has been measured as a function of potassium coverage. Distinct minima of the noise power for coverages that correspond exactly to the work function minima could be found. It seems that this coincidence might be explained — apart from big lateral interactions of the adparticles — by the stronger adsorbate-substrate interaction in a coherent adiayer than in an incoherent one and/or by an adlayer transition to the “metallic” state resulting in compensation of the ionic adsorbate charge by a common electron gas.