We have grown polycrystalline GaN both on polycrystalline Mo sheets and on Si(001) substrates with native oxide by using plasma-assisted molecular beam epitaxy. It has been found that GaN growth on Si(001) with native oxide produces well corientated nanorods exhibiting a low field emission threshold of 1.25 V/μm at 0.1 μA/cm2 and a high emission current density of 2.50 mA/cm2 at an applied electric field of 2.5 V/μm. We will review the growth of polycrystalline GaN films and the evaluation of their structural properties and electron field emission characteristics.

Keywords: polycrystalline GaN, plasma-assisted MBE, field electron emission, nanorod