Shockley–Read–Hall lifetime in homoepitaxial p-GaN extracted from recombination current in GaN p–n+ junction diodes

The Shockley-Read-Hall (SRH) lifetime in homoepitaxial p-GaN (N-a = 1 x 10(17) cm(-3)) is investigated by analyzing forward current-voltage (I-V) characteristics in GaN-on-GaN p-n(+) junction diodes with mesa-isolation structure. The ideality factor around 2 due to recombination current was obtained in the 1.8-2.7 V window, which is different from the characteristic of a p(+)-n(-) junction involving considerable diffusion current. The recombination current was proportional to the junction area, indicating that the recombination current is a bulk component, not a mesa-surface component. Analyzing the recombination current with consideration of the SRH recombination rate in the depletion layer, we obtained an SRH lifetime of 46 ps at 298 K. The temperature dependence of the I-V characteristics was also investigated and the SRH lifetimes were extracted in the range of 223-573 K. The SRH lifetime in homoepitaxial p-GaN followed the empirical power law of tau(SRH) = 1.2 x 10(-16) x T-2.25 (s). (C) 2019 The Japan Society of Applied Physics