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 ∼10 kA/cm2, low off currents < 10(−5) A/cm2, on/off current ratio of > 10(9), and interband photon emission. The measured electroluminescence spectrum is dominated by 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 ∼2.2 MV/cm without fields plates – the highest reported for N-polar epitaxial structures. The low leakage current N-polar diodes photonic and electronic devices.