Field emission from quasi-aligned aluminum nitride nanotips

We report the field emission properties of the quasi-aligned aluminum nitride (AlN) nanotips grown on differently doped (p+, p, n+, and n type) silicon (Si) substrates by thermal chemical vapor deposition. The AlN nanotips were 10nm at the apex, 100nm at the bottom, and 1200nm in length. The AlN nanotips grown on p+-Si substrate showed the lowest turn-on field of 6V∕μm (highest current density of 0.22A∕cm2 at a field of 10V∕μm), whereas no significant emission could be obtained using n+- and n-Si substrates. Band diagrams of the Si–AlN heterojunction have been used to explain the phenomenon. A 5% variation of the applied field was observed while drawing a current density of 100μA∕cm2 from the nanotips grown on p+-Si substrates.