Growth and field-emission properties of crystalline, thin-walled carbon microtubes

A crystalline graphitic structure -uniform diameter, thin-walled carbon microtubes (see Figure) -has been prepared via a thermal reaction between ZnS and activated carbon. The microtubes have outer diameters of similar to1-2 mum, wall thicknesses of 10-20 nm, and lengths from several hundreds of micrometers to millimeters. The field-emission turn-on of the carbon microtubes is as low as similar to 1.0-1.3 V mum(-1).