Single-crystalline GdB6 nanowire field emitters.

Having the lowest work function in the rare-earth hexaboride family, GdB6 nanowires of rectangular cross-section with about 50 nm in lateral dimension and several microns in length have been successfully produced using a CVD method. The nanowires are grown in the 001 lattice direction, and both the tip-top and the side surfaces are terminated with the {100} lattice planes. A GdB6 single nanowire field emitter has also been built with an emission current of more than 150 nA at an applied field of less than 3.2 V/mum. The work function of the nanowire emitter was estimated to be about 1.5 eV.