Sulfur doped nanocrystalline diamond films as field enhancement based thermionic emitters and their role in energy conversion

Contributors:   F.A.M. Koeck, and Robert J. Nemanich

ABSTRACT

Sulfur doped nanocrystalline diamond films, like other nanostructured carbon films, exhibit electron emission characterized by a spatial non-uniformity of the field enhancement factor. While field emission effects are observed at room temperature, an increase in emitter temperature is accompanied by an amplified emission current with a simultaneous drop in the threshold field. At low extraction fields a fit of the emission current to the Richardson equation indicates a material work function of ∼2.5 eV. The Schottky formula describes thermionic emission at a moderate field and is utilized to determine the work function at an electric field of 0.8 V/μm with a value of ∼1.7 eV and a concurrently reduced Richardson constant. This significant difference in the work function of 2.5 and 1.7 eV for 0.5 and 0.8V/μm, respectively can be attributed to field enhancement effects

Publisher: Diamond and Related Materials,   Volume: 14,   Published: 2005-10 ||   PDF (179.77 KB) ||   Read more...