Controlled growth and field-emission properties of NbSe2 micro/nanostructured films

Single-crystalline NbSe2 nanobelt, nanorod (containing nanotube), and microplate films were grown on Nb substrates by a surface-assisted chemical-vapor-transport (CVT), respectively. The nanobelts have a rectangular section of 50 x 250 to 300 x 4500 nm2, and a length up to 330 microm. The nanorods have a hexagonal section with a diameter of about 0.1-0.5 microm, and a length up to 15 microm. The nanotubes have rectangular, pentagonal or round sections with a diameter of about 0.4-0.5 microm, a tube-wall thickness of about 45 nm, and a length up to several microns. The microplates have a hexagonal section with a diameter of about 0.05-10 microm and a thickness of about 100 to 600 nm. Field-emission experiments using the films as cold electron cathodes showed that they had notable emission currents and low turn-on fields, suggesting their potential applications in field emission devices.