Preparation and Field Emission Properties of Titanium Polysulfide Nanobelt Films

TiS3 nanobelt films, with widths of about 0.1-12 mu m, thickness of about 20 250 nm, and lengths of up to 200 mu m, have been grown on Ti substrates by a surface-assisted chemical-vapor-transport at 450 degrees C for 8 h. The TiS3 nanobelt films were converted into TiS1.71 nanobelt films by pyrolysis in a vacuum at 600 degrees C for 2 h. The work functions of the two films were determined by ultraviolet photoelectron spectroscopy measurements to be 4.60 and 4.44 eV, respectively. Preliminary field emission experiments using the nanostructures as cold electron cathodes showed that both materials gave significant emission currents. The turn-on fields ( defined as the electric field required to produce a current density of 10 mu A/cm(2)) were about 1.0 and 0.9 V/mu m, respectively, whereas the threshold fields (defined as the electric field required to produce a current density of 1 mA/cm(2)) were about 5.6 and 4.0 V/mu m, respectively. These data reveal that both materials have potential applications in field emission devices.