Prof. Masayuki Nakamoto, Doctor, Graduate School of Integrated Science and Technology, Shizuoka University, Japan

Title: Stable and Environment-Hard Vacuum Nanoelectronic Devices for Aerospace Applications

Abstract: Extremely stable field-emitter arrays (FEAs) having low work function as well as resisting harsh environments have been fabricated by the Transfer Mold emitter fabrication method to make highly resistant vacuum nanoelectronic devices that operate at low voltage in harsh environments such as a strong radical atmosphere. Whereas conventional FEAs such as carbon-nanotube FEAs have non-uniform tip radii, Transfer Mold FEAs are very uniform and differ in height and pitch from conventional FEAs. Amorphous carbon (a-C) and titanium nitride (TiN), which not only have a low work function but also resist harsh environments, were used as the emitter material. The emission fluctuation rates of a-C FEAs even without resistive layers were as low as ±1.7%, which is one of the lowest ever reported, compared with 5–100 % for conventional FEAs with resistive layers. The a-C FEAs exhibit the most stable emission characteristics compared with Transfer Mold FEAs coated with TiN or Pt (TiN-FEAs or Pt-FEAs) because a-C FEAs have the most uniform tip radii. The a-C FEAs and TiN-FEAs exhibit stable fluctuations of less than ±5.1% even under in situ oxygen radical treatment. Panel and pixel electric thrusters have been proposed that use Transfer Mold FEAs. These electric thrusters make it easy to produce large and small thrusters. The a-C FEAs exhibit very stable field-emission characteristics and the highest resistance to harsh environments. Therefore, they can be used to make highly efficient and reliable vacuum electronic devices such as electric propulsion engines and field-emission displays.

Keywords: Transfer Mold emitter fabrication method, field emitter arrays, vacuum nanoelectronic devices, environment-hard, electric propulsion engines