Enhanced electron field emission from micropatterned pyramidal diamond tips incorporating CH_4/H_2/N_2 plasma-deposited nanodiamond

摘要

Enhanced field emission is observed from micropatterned pyramidal diamond tips fabricated with CH_4/H_2/N_2-deposited nanodiamond. Nanodiamond films with grain size as small as approx 5 nm from the process with CH_4/H_2/N_2 MPECVD and approx 20 nm from CH_4/H_2 MPECVD were formed by employing a growth-rate control technique. The nanodiamond films grown by the 2 different gas chemistries were applied individually in the fabrication of micropatterned pyramidal diamond tip arrays through a mold transfer technique and characterized for field emission. The CH_4/H_2 nanodiamond tips showed a turn-on field of - 14 V/um; the CH_4/H_2/N_2-nanodiamond tips exhibited significantly enhanced field emission characteristics with a low threshold field of 1.6 V/mu m (electric field reduction > 80 percent) and a high emission current of 19 mA at 6 V/mu m. The improved field emission behavior of the CH_4/H_2/N_2-nanodiamond tip array is attributed to its better geometrical enhancement factor (beta_g=32,000), increased sp~2-carbon content and higher electrical conductivity by incorporation of nitrogen impurity in the diamond. The emission characteristics obtained from the nitrogen-incorporated nanodiamond imply a useful candidate for cold field emission cathodes.