Influence of carrier screening and band filling effects on efficiency droop of InGaN light emitting diodes.

In this paper, the self-consistent solution of Schrödinger-Poisson equations was realized to estimate the radiative recombination coefficient and the lifetime of a single blue light InGaN/GaN quantum well (QW). The results revealed that the recombination rate was not in proportion to the total injected carriers, and thus the Bnp item was not an accurate method to analyze the recombination process. Carrier screening and band filling effects were also investigated, and an extended Shockley-Read-Hall coefficient A(kt) with a statistical weight factor due to the carrier distributions in real and phase space of the QW was proposed to estimate the total nonradative current loss including carrier nonradiative recombination, leakage and spillover to explain the efficiency droop behaviors. Without consideration of the Auger recombination, the blue shift of the electroluminescence spectrum, light output power and efficiency droop curves as a function of injected current were all investigated and compared with the experimental data of a high brightness blue light InGaN/GaN multiple QWs light emitting diode to confirm the reliability of our theoretical hypothesis.