Fabrication and field emission study of atomically sharp high-density tungsten nanotip arrays

Atomically sharp high-density tungsten nanotip arrays are fabricated by nanocasting using a patterned SiO2 template. The fabrication involves mainly top-down processes making it fully compatible with today’s Si technology. The obtained tungsten nanotip arrays show atomically sharp tips (radius of curvature smaller than 1 nm), high emitter density (∼5×1010 cm−2), perfect tip alignment, and excellent field emission properties with a turn-on field of 2.1 V/μm and a field enhancement factor of 3334. The unique fabrication process flow leads to the highly uniform height of the W nanotips, allowing for submicron cathode-anode spacing, which very much relaxes the requirement of vacuum level and makes it possible for low vacuum operation.