Improved field emission properties from polycrystalline indium oxide-coated single-walled carbon nanotubes

Abstract

The field emission (FE) characteristics of indium oxide (In2O3)-coated single-walled carbon nanotubes (SWCNTs) were studied. Scanning electron microscopy, x-ray diffractometer, and UV/visible spectroscopy confirmed that In2O3 exists as a polycrystalline cubic bixbyite structure on the surface of SWCNTs. The turn-on field of pristine SWCNTs decreased from 3.82 to 3.27 V/mu m for In2O3-coated SWCNTs with optimal coating thickness. The maximum emission current density reached 3.5 mA/cm(2), five times higher than that of pristine SWCNTs (0.68 mA/cm(2)) at an electric field of 7 V/mu m. To explain the higher FE current density of In2O3-coated SWCNTs, Fowler-Nordheim plots were used with some assumptions.