Enhanced electron field emission from micropatterned pyramidal diamond tips incorporating CH4/H2/N2 plasma-deposited nanodiamond

• Published in: Diamond and related materials 2006-04, Vol.15 (4-8), p.1126-1131
• Main Authors: Subramanian, K, Kang, W R, Davidson, J L, Takalkar, R S, Choi, B K, Howell, M, Kerns, D V
• Format: Article
• Language: English
• ISSN: 0925-9635
• DOI: 10.1016/j.diamond.2005.12.047

Enhanced field emission is observed from micropatterned pyramidal diamond tips fabricated with CH4/H2/N2-deposited nanodiamond. Nanodiamond films with grain size as small as ~ 5 nm from the process with CH4/H2/N2 MPECVD and ~ 20 nm from CH4/H2 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 CH4/H2 nanodiamond tips showed a turn-on field of ~ 14 V/mum; the CH4/H2/N2-nanodiamond tips exhibited significantly enhanced field emission characteristics with a low threshold field of 1.6 V/mum (electric field reduction > 80%) and a high emission current of 19 mA at 6 V/mum. The improved field emission behavior of the CH4/H2/N2-nanodiamond tip array is attributed to its better geometrical enhancement factor (betag=32,000), increased sp2-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.