Patent ID: 6891319

Claim:
A field emission device including an anode and a cathode, said cathode comprising; a substrate having a deformation temperature that is less than about six hundred and fifty degrees Celsius; a nano-supported catalyst formed on said substrate, said nano-supported catalyst having active catalytic particles that are less than about five hundred nanometers in diameter, the nano-supported catalyst comprising: a non-porous sub-layer, overlying the substrate, having said active catalytic particles and a structural metallic element; and a porous sub-layer, overlying the non-porous sub-layer, having said active catalytic particles supported by a metal oxide structure; and a plurality of nanotubes that are catalytically formed in situ on said nano-supported catalyst, each of said plurality of nanotubes having a diameter that is less than about twenty nanometers and configured to provide a switching voltage for triggering nanotube emission that is less than about eighty volts so that a nanotube emission current density drawn from said field emission device is greater than about one-half milliampere per squared centimeter of said anode.