Improvement of diamond nanocomposite field emitters by oxidation

Improvement of diamond nanocomposite field emitters by oxidation is studied. Results show that the oxidized composites exhibit lower emission threshold fields E_th=1-2 V/μm as measured with a flat screen technique. The emission uniformity (the number of emission sites per unite area) was also improved. The composites with low sp²-bonded carbon content, i.e. more porous samples, show better results. The structure of the nanocomposites was studied using microRaman spectroscopy, SEM, and Auger electron spectroscopy. Electronic properties of the emission centers (work function, electrical conductivity, topography and emission intensity) were investigated with a special STM device. The possible mechanisms of the emission improvement by oxidation in this two-phase carbon system are also discussed.