We study the carrier dynamics for c-plane InGaN/GaN light-emitting diodes (LEDs) with various emission wavelengths near the green gap using a small-signal electroluminescence method. The LEDs were grown by Lumileds using state-of-the-art growth conditions. Radiative and non-radiative recombination rates are numerically separated, and the carrier recombination lifetime and carrier density are obtained. Experiment shows that the causes of efficiency reduction at longer wavelength in the present structures are injection efficiency decrease, radiative recombination rate decrease, and imbalance of the increase in Auger–Meitner and radiative terms due to the interplay between the carrier–current density relationship and the quantum-confined Stark effect (QCSE). The effects of QCSE, phase-space filling, and the carrier–current density relationship on efficiency reduction at longer wavelengths are examined separately with experimental data and Schrödinger–Poisson calculations. In addition, we confirm the scaling law between Cn and Bn under electrical injection and find that the increase in carrier density at a given current density is the primary cause for lower radiative efficiency at high current density in longer wavelength LEDs. Conversely, we do not observe a significant efficiency reduction at longer wavelengths from extrinsic material degradation.

中文翻译：

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通过小信号电致发光测量蓝色、青色和绿色 InGaN/GaN LED 的载流子动力学

我们使用小信号电致发光方法研究了在绿色间隙附近具有各种发射波长的 c 面 InGaN/GaN 发光二极管 (LED) 的载流子动力学。LED 由 Lumileds 使用最先进的生长条件生长。辐射复合率和非辐射复合率在数值上分开，并获得载流子复合寿命和载流子密度。实验表明，当前结构中较长波长处效率降低的原因是注入效率降低、辐射复合率降低，以及由于载流子-电流密度关系与量子限制斯塔克效应 (QCSE)。QCSE、相空间填充的影响，载流子-电流密度关系对较长波长下效率降低的影响分别通过实验数据和薛定谔-泊松计算进行了检验。此外，我们确认了电注入下 Cn 和 Bn 之间的比例定律，并发现在给定电流密度下载流子密度的增加是较长波长 LED 在高电流密度下辐射效率较低的主要原因。相反，我们没有观察到外部材料降解导致较长波长的效率显着降低。我们确认了在电注入下 Cn 和 Bn 之间的比例定律，并发现在给定电流密度下载流子密度的增加是较长波长 LED 在高电流密度下辐射效率较低的主要原因。相反，我们没有观察到外部材料降解导致较长波长的效率显着降低。我们确认了在电注入下 Cn 和 Bn 之间的比例定律，并发现在给定电流密度下载流子密度的增加是较长波长 LED 在高电流密度下辐射效率较低的主要原因。相反，我们没有观察到外部材料降解导致较长波长的效率显着降低。