Patterned growth and field-emission properties of AlN nanocones.

Patterned growth of AlN nanocones on a Ni-coated Si substrate is demonstrated through the reaction between AlCl(3) and NH(3) at 700 degrees C with Mo grid as a mask. The AlN nanocones are selectively deposited in the hollow region of the mask with diameters of approximately 10 nm at the tips and 50-60 nm at the roots. The field-emission (FE) performance is effectively enhanced by the patterned growth mainly because of the decreased screening effect, and both turn-on and threshold fields are dramatically decreased, less than half of the corresponding ones for the unpatterned product with similar sizes. The results indicate that patterned growth is an efficient and reproducible way to enhance the FE performance of AlN nanocones, which could be applied to optimize the FE properties of other nanoscale field emitters.