Nanodiamond planar lateral field emission diode

Abstract

We report the fabrication and field emission characteristics of the nanodiamond planar lateral field emission diode. Nanodiamond films with grain size as small as 5–10 nm have been realized through the process of CH 4/H 2/N 2 microwave plasma enhanced chemical vapor deposition (MPECVD) by employing an effective growth rate reduction technique. Well-controlled processes have been developed; including reactive ion etch (RIE) to pattern the nanodiamond films to fabricate lateral field emission devices with planar lateral fingers. An anode–cathode spacing of 2 μm between the nanodiamond anode and cathode has been achieved. A nanodiamond lateral diode equipped with 6 fingers and an inter-electrode separation of 3 μm exhibits a turn-on voltage of 5.9 V (threshold electric field of 1.9 V/μm), one of the lowest reported for lateral field emission devices, and a high emission current of 1.1 mA (∼ 183 μA current per finger) at an anode voltage of 100 V (∼ 30 V/μm). The emission current is found to be stable with ∼ 4% fluctuation at 1 mA over 10 h. The nanodiamond lateral device is very promising for applications in vacuum nanoelectronics, sensors, and nanoelectromechanical systems.