ELECTRON FIELD-EMISSION FROM DIAMOND AND OTHER CARBON MATERIALS AFTERH-2, O-2 AND CS TREATMENT

This letter reports, diamond field emitters, Cs treated, air stable, t hat emit electrons at the lowest reported field, <0.2 V mu m(-1). Fiel d emission from B-, Li-, P-, and N-doped diamonds and carbonized polym er was characterized as a function of surface treatment. A treated wit h an O-2 plasma, coated with Cs, heated, and exposed to O-2 exhibited increased emission for all samples except for B-doped diamond. The bes t emission was obtained from N-doped diamond samples, followed by carb onized polymer, the Li-doped, and polycrystalline P-doped diamond. Li- and N-doped samples treated with Cs were stable in laboratory air for several days. This stability of the surface-activated diamond is beli eved to be due to the formation of a diamond-O-Cs salt. If the sample is treated with a H-2 plasma instead of an O-2 plasma, the Cs-enhanced emission degrades with heat and exposure to O-2. Subbands formed by L i and N impurities are believed to be responsible for this enhanced em ission. The surface treatment on N-doped diamond results in emission a t fields as low as 0.2 V mu m(-1). (C) 1995 American Institute of Phys ics.