Field emission characteristics of BN/GaN structure

n -type gallium nitride (GaN) layers grown on sapphire substrates by metalorganic chemical vapor deposition are used to examine field emission characteristics. The electron concentration of the GaN is 2×1017 cm−3. In order to enhance the electric field, the GaN surface is roughened by hydrogen (H2) plasma treatment. Boron nitride (BN) films are grown on the roughened surface of the GaN by plasma-assisted chemical vapor deposition. The turn-on electric field between the anode and sample surface is estimated to be 12.4 and 8.8 V/μm from the field emission characteristics of the roughened GaN and the BN/GaN samples, respectively. It is demonstrated that BN coating is effective in improving the field emission characteristics.