Internal quantum efficiency droop of GaN LED

Begin with the carrier equation, the relationship between the carrier generation rate G and the integrated photoluminescence intensity I_PL can be obtained. And the internal quantum efficiency (IQE) of InGaN/GaN MQWs can be determined from the dependence of integrated PL intensity on excitation power. The photoluminescence of a LED sample with Charge Asymmetric Resonance Tunneling (CART) structure were studied. The experimental data shows that the peak from InGaN quantum well shifts blue and its integrated intensity increases slowly when the exciting power increases. And the IQE of this LED chip decreases as the exciting power increasing.