Nonpolar vertical GaN-on-GaN p-n diodes grown on free-standing (10(1)over-bar0) m-plane GaN

We report nonpolar vertical GaN-on-GaN p-n diodes grown on rn-plane free-standing substrates. Cathodoluminescence measurements showed that the nonpolar p-GaN had a high quality with very few deep-level states. The device exhibited good rectifying behaviors with a turn-on voltage of 4.0 V, on-resistance of 2.3 m Omega.cm(2), and high on/off ratio of 10(10). The reverse current leakage was described by a trap-assisted space-charge-limited current conduction mechanism. The critical electrical field was calculated to be 2.0 MV/cm without field plates or edge termination. These results pave the way for development of novel nonpolar power electronics and polarization-engineering-related advanced power devices. (C) 2018 The Japan Society of Applied Physics