Field Emission from Polycrystalline GaN Grown on Mo Substrate

Polycrystalline GaN layers are grown on polycrystalline Mo substrate by gas source molecular beam epitaxy using an ion removal electron cyclotron resonance radical cell. Electronic transport across the GaN/Mo interface shows ohmic characteristics. Atomic force microscopy observation shows grain structures of GaN with a grain size of 300–600 nm. Field emission measurement is carried out on the polycrystalline GaN/Mo samples. A turn‐on electric field of the electron emission is estimated to be as low as 6.4 V/μm at an emission current density of 10 —8 A/cm 2 . The field enhancement factor estimated from a Fowler–Nordheim plot is about 200.