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Articles you may be interested inThe effect of silicon doping in the barrier on the electroluminescence of InGaN/GaN multiple quantum well light emitting diodes Carrier recombination mechanisms in nitride single quantum well light-emitting diodes revealed by photo-and electroluminescence J. Appl. Phys.Light emitting diodes ͑LEDs͒ using InGaN/GaN quantum wells ͑QWs͒ with thin low temperature GaN ͑LT-GaN͒ layers bounding each InGaN layer are grown by metal-organic vapor phase epitaxy. The light output power of such LEDs increases by a factor of 2 at a drive current density of 35 A / cm 2 compared to that from reference LEDs without the LT-GaN. The blueshift in the emission wavelength is 5.2 nm when the current density increases from 3 to 50 A / cm 2 , which is much smaller than the shift 8.1 nm from reference LEDs. Moreover, the efficiency droop at high current injection is also reduced by 28%, and current density at which peak efficiency is observed increases from 1 to 2 A / cm 2 . High resolution transmission electron microscopy of the QWs bounded with LT-GaN shows higher quality and less strain compared to the reference samples. The better performance of LEDs incorporating the LT-GaN layers is attributed to suppressed polarization from piezoelectric fields.

Derating of the working current level does not work for improving GaN-based light-emitting diode (LED) devices' reliability. The present work demonstrates that it is not the levels but the specific components of the applied electrical currents weighing more on LEDs' degradation. Existing defects are sources for tunneling currents and Shockley-Read-Hall (SRH) non-radiative recombination current, and the component of tunneling currents and SRH non-radiative recombination current in the applied electrical current will in turn induce fast increase of defect density. The current component from electron tunneling to deep levels in the vicinity of mixed/screw dislocations will affect more on LEDs' degradation than other components, such as heavy-hole tunneling via intermediate state. In a whole, the overflow leakage current from the active region and Auger recombination currents in the applied electrical current will generate positive effects to alleviate LEDs' degradation.