Efficiency droop behaviors of InGaN∕GaN multiple-quantum-well light-emitting diodes with varying quantum well thickness

In Ga N ∕ Ga N multiple-quantum-well (MQW) light-emitting diodes with varied InGaN quantum well thicknesses are fabricated and characterized. The investigation of luminous efficiency versus current density reveals a variety of efficiency droop behaviors. It is found that the efficiency droop can be drastically reduced by increasing the quantum well thickness of the MQW structures. On the other hand, relative internal quantum efficiency (IQE) measurements indicate that a thinner well results to higher IQEs owing to the greater spatial overlap of electron and hole distribution functions.