Abstract: A method for measuring work function includes the steps of: (a) providing a field emission electron source having a carbon nanotube tip as a cathode electrode and a spaced anode electrode, having a predetermined spaced distance therebetween; (b) applying a voltage between the cathode electrode and the anode electrode and measuring a first current-voltage curve of the field emission electron source in a vacuum environment; (c) forming a layer of field emission material at least on the surface of the carbon nanotube tip; (d) measuring a second current-voltage curve of the now-treated field emission electron source in the same conditions as that in the step (b); (e) achieving two Fowler-Nordheim curves calculated from the two current-voltage curves according to the Fowler-Nordheim equation; and (f) comparing the two Fowler-Nordheim curves and calculating the work function of the field emission material therefrom.

Abstract: A method for growing an array of carbon nanotubes includes the steps of: (a) providing a substrate having a first substrate surface and a second substrate surface opposite to the first substrate surface; (b) forming a catalyst film on the first substrate surface; (c) flowing a mixture of a carrier gas and a first carbon source gas over the catalyst film on the first substrate surface; (d) focusing a laser beam on the second substrate surface to locally heat the substrate to a predetermined reaction temperature; and (e) growing an array of the carbon nanotubes on the first substrate surface via the catalyst film.