The enhancement of electron field emission was successfully obtained from carbon nanofiber (CNF) bundles separately grown on Ni grains in Ni-Cr alloy compared with that from CNF bundles on pure nickel. Ni grains less than 1 μm in size were separated by Cr grains in the alloy prepared by cosputtering with Ni pellets on a Cr plate without a lithographic patterning process. CNFs grew on Ni grains as bundles of 100 nm diameter and 1 μm length by helicon wave plasma-enhanced chemical vapor deposition, controlling the distance between adjacent CNF bundles by 500-1000 nm. The field emission characteristics of electrons from CNF bundles were evaluated and compared using current-voltage characteristic curves and a Fowler-Nordheim (F-N) plot converted using a work function value of 4.7 eV for CNFs. The field enhancement factor of FE characteristics obtained from the slopes in the F-N plot increased with the average distance defined as the space between adjacent CNF bundles. CNFs separately grown on a Ni-Cr catalyst are a candidate for effective two-dimensional field emitter devices.
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