Preparation and field emission properties of titanium polysulfide nanobelt films

TiS 3 nanobelt films, with widths of about 0.1–12 μm, thickness of about 20–250 nm, and lengths of up to 200 μm, have been grown on Ti substrates by a surface-assisted chemical-vapor-transport at 450 °C for 8 h. The TiS 3 nanobelt films were converted into TiS 1.71 nanobelt films by pyrolysis in a vacuum at 600 °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 μA/cm 2 ) were about 1.0 and 0.9 V/μm, 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/μm, respectively. These data reveal that both materials have potential applications in field emission devices.