Single-crystal N-polar GaN p-n diodes by plasma-assisted molecular beam epitaxy

N-polar GaN p-n diodes are realized on single-crystal N-polar GaN bulk wafers by plasma-assisted molecular beam epitaxy growth. The current-voltage characteristics show high-quality rectification and electroluminescence characteristics with a high on currents similar to 10 kA/cm(2), low off currents <10(-5) A/cm(2), on/off current ratio of >10(9), and interband photon emission. The measured electroluminescence spectrum is dominated by a strong near-band edge emission, while deep level luminescence is greatly suppressed. A very low dislocation density leads to a high reverse breakdown electric field of similar to 2.2 MV/cm without fields plates-the highest reported for N-polar epitaxial structures. The low leakage current N-polar diodes open up several potential applications in polarization-engineered photonic and electronic devices. Published by AIP Publishing.