Characteristics of InGaN light emitting diode depending on Si-doping on InGaN layers below quantum wells

•Si-doped layers below QWs determine charge concentration in the depletion region.•Four different levels of Si-doping below QWs have been produced for the experiment.•Reverse leakage current can be decreased by lowering Si-doping below QWs.•Light output power can be enhanced by lowering the background charge concentration.•Low background charge concentration improves the device lifetime of InGaN LED.

Effect of Si-doping on InGaN layers below the quantum wells (QWs), which cause different levels of charge concentration in the depletion region, have been investigated for InGaN light emitting diodes (LEDs). Four groups of InGaN LEDs with different levels of Si-doping on InGaN/GaN layers below quantum-wells have been produced for the experiment (i.e., 0.5 × 1017 cm−3 for group A, 1 × 1017 cm−3 for group B, 5 × 1017 cm−3 for group C, and 1 × 1018 cm−3 for group D.) The reverse leakage current of LED can be significantly decreased and the light output power of LED can be enhanced by lowering the background charge concentration in the depletion region of LED. Such result enables us to improve the device lifetime by inhibiting the degradation of the GaN-based LED.