Nanostructured LaB₆ field emitter with lowest apical work function

LaB₆ nanowires are ideal for applications as an electrical field-induced ion and electron point source due to their miniature dimensions, low work function, as well as excellent electrical, thermal, and mechanical properties. We present here a reliable method to fabricate and assemble single LaB₆ nanowire-based field emitters of different crystal orientations. The atomic arrangement, emission brightness from each crystal plane, and field emission stability have been characterized using field ion microscopy (FIM) and field emission microscopy (FEM). It is found that the 〈001〉 oriented LaB₆ nanowire emitter has the highest field emission symmetry while the 〈012〉 oriented LaB₆ nanowire has the lowest apical work function. The field emission stability from the single LaB₆ nanowire emitter is significantly better than either the LaB₆ needle-type emitter or W cold field emitters.