Electron field emission from boron nitride nanofilm and its application to graphite nanofiber

GaN layers are grown on sapphire substrates with AlN buffer layers by the metalorganic chemical vapor deposition method. GaN layers are doped with Si. The electron density of the n-type GaN is 2×1017 cm−3. It is found that the GaN surface is etched with hydrogen (H2) plasma produced by supplying microwave power leading to the formation of the roughened surface of GaN. A variation in the surface morphology occurs due to microwave power and gas pressure. Field emission measurements are carried out for GaN with various surface morphologies. It is observed that the turn-on electric field decreases with increasing surface roughness of the GaN. A turn-on electric field of the electron emission is estimated to be as low as 12.4 V/μm.

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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.

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