Based on time-resolved electroluminescence (TREL) measurement, more efficient carrier injection, transport, relaxation, and recombination associated with a stronger carrier localization and a low polarization effect in a nonpolar m-plane InGaN/GaN light emitting diode (m-LED), compared with those in a polar c-LED, are reported. With a higher applied voltage in the c-LED, decreasing response time and rising time improve device performance, but a longer recombination time degrades luminescence efficiency. By using an m-LED with a stronger carrier localization and a low polarization effect, shorter response, rising, and recombination times provide more efficient carrier injection, transport, relaxation, and recombination. These advantages can be realized for high-power and high-speed flash LEDs. In addition, with a weaker carrier localization and a polarization effect in the c-LED, the slower radiative and faster nonradiative decay rates at a larger applied voltage result in the slower total decay rate and the lower luminescence efficiency. For the m-LED at a higher applied voltage, a slow decreasing nonradiative decay rate is beneficial to device performance, while the more slowly decreasing and overall faster radiative decay rate of the m-LED than that of the c-LED demonstrates that a stronger carrier localization and a reduced polarization effect are efficient for carrier recombination. The resulting recombination dynamics are correlated with the device characteristics and performance of the c- and m-LEDs.

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In this study, the effects of precursor duration and thermal annealing on the material and optical properties of InGaN/GaN multiple quantum wells (MQWs) grown on nitrogen (N)-polar GaN templates by a pulsed metallorganic chemical vapor deposition are investigated. With a 2-sec NH 3 precursor duration, an apparent indium aggregation leads to a higher density and larger size of InGaN mounds for more exciton accumulation, enhancing the radiative recombination and luminescence efficiency. In addition, the more, larger, and brighter light spots in the cathodoluminescence (CL) images and a stronger CL intensity in the annealed sample show that a smaller size and higher density of InGaN mounds enhance the radiative recombination and luminescence efficiency. Both a 2-sec NH 3 precursor duration and 60-sec thermal annealing are beneficial to the growth conditions of InGaN/GaN MQWs grown on N-polar GaN templates. The research results of the pulsed growth mode provide important information to optimize growth conditions of InGaN/GaN MQWs grown on N-polar GaN templates.