Enhanced Field Emission Properties of Carbon Nanotube Based Field Emitters by Dynamic Oxidation

Carbon Nanotubes (CNTs) are purified by Dynamic-oxidation (D-oxidation) technique to enhance the field emission behavior of CNT field emitters. In D-oxidation method, Carbon-type (C-type) impurities are removed out by selective oxidation by heating at constantly increasing temperature in air. It is observed that the turn-on voltage of D-oxidized CNTs is decreased from 4.4 V/μm to 3.6 V/μm, the current density is enhanced from 0.014 mA/cm2 to 1.12 mA/cm2 at an electric field of 6.4 V/μm and effective emitting area is increased from ∼ 2.18 x10-12 cm2 to 1.09 x10-9 cm2. These findings may be due to the removal of C-type impurities from the surface of CNTs during D-oxidation which exposes the large effective area for emission of electrons leading to enhanced emission current even at low turn-on voltage.