Field Emission from Low Density Carbon Nanofiber Emitters Prepared by Spray Spreading Method

Abstract

The purposes of this work are to prepare a low density carbon nanofibers (CNFs) emitter by a spray spreading method and to investigate the performance of field emission. Sprayed paste was prepared with organic solution of tetrahydrofuran and also with binders of Au paste and polycarbonate. The used CNFs were massively synthesized by a thermal chemical vapor deposition and were burned to eliminate amorphous carbon and catalyst. The diameter of the CNFs was about 0.1 µmφ. Two types of CNFs were studied with the length of ca. 20 µm (normal-CNF) and ca. 1.5 µm (cut-CNF). In the normal-CNFs emitter the current density at 10 V/µm was about 1.4 mA/cm2 with an electric field enhancement factor β of about 1000, while about 0.08 mA/cm2 with β of 4500 in the cut-CNFs emitter. It was confirmed that isolated CNFs do play an important role as effective emitter sites.