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 10 nm at the apex, 100 nm at the bottom, and 1200 nm in length. The AlN nanotips grown on p+ -Si substrate showed the lowest turn-on field of 6 Vμm (highest current density of 0.22 A cm2 at a field of 10 Vμm), 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 100 μA cm2 from the nanotips grown on p+ -Si substrates.