Ammono, the manufacturer of high-quality GaN substrates by ammonothermal method is pleased to announce, that researches from School of Electrical and Computer Engineering, Department of Materials Science and Engineering, Cornell University (USA) realized N-polar GaN p-n diodes on monocrystalline Ammono-GaN substrates using plasma-assisted Molecular Beam Epitaxy (PA-MBE) technique.

Most of the nitride optoelectronic and electronic devices are based on structures grown in Ga-polar direction. However, epitaxy along N-polar direction could offer improved features of the grown quantum structures, such as creating electron-blocking layers with reduced barriers, effective polarization-induced p-type doping, opportunity of making epitaxial growth at higher temperatures, improved characteristics of high-frequency and high-power transistors resulting from different carrier distribution in opposite direction of internal polarization fields. By taking advantage of available N-polar oriented bulk Ammono-GaN substrates of very low dislocation density (104 cm-2) and high structural perfection, high quality N-polar p-n diodes comparable to state-of-the-art Ga-polar counterparts was demonstrated and published recently in Appl. Phys. Lett. 110, 253506 (2017).

The current-voltage characteristics of obtained diode show high-quality rectification and electroluminescence properties with a high on-currents 〜 10kA/cm2, low off-currents < 10‑5 A/cm2, on/off ratio of >109, and strong near-band edge dominated emission. A very low dislocation density leads to a high reverse breakdown electric field of about 2.2 MV/cm – the highest reported ever for N-polar epitaxial structures. The authors say, that further enhancement of the diode performance is expected after electrically isolating the device region from edge sidewalls by using so-called field plates.

Published result shows, that a milestone towards the realization of a number of new device possibilities was achieved. By offering products of outstanding properties, Ammono is highly engaged in such new non-standard approaches on GaN-based device technology, creating new directions of development.

For more details about N-polar oriented bulk GaN substrates, please contact our team.