线性分布的In组分对紫色InGaN/GaN单量子阱发光特性的影响

Influence of Linear Distributed In Composition on The Luminescence Characteristics of Violet InGaN/GaN Single Quantum Well

采用数值模拟的方法研究了具有相同的平均In组分,但In组分的分布不同的3个紫色InGaN/GaN单量子阱样品的光谱特性。通过分析样品的电致发光谱、能带结构、波函数交叠以及载流子浓度分布等,发现沿生长方向阱内In组分线性增加的单量子阱样品的发光效率最高,而In组分线性减小的样品发光效率最低。这是因为In组分的线性增加能够减弱极化场对价带的影响,使阱内价带变得更加平缓。这不仅降低了空穴的注入势垒高度、增大了阱中的空穴浓度,还增强了阱内电子-空穴波函数的交叠积分,提高了辐射复合几率,从而使In组分线性增加的量子阱的发光效率显著提高。

The spectral characteristics of three violet InGaN/GaN single quantum well samples with the same average In composition but different In composition distributions are studied in this paper.By analyzing the electroluminescence spectra,energy band structures,wave function overlap and carrier concentration distribution,it is found that the single quantum well sample with linearly increased In composition along the growth direction has the highest luminescence efficiency,while the sample with linearly decreased In composition has the lowest luminescence efficiency.It is considered that the linear increase of the In composition can weaken the influence of the polarization field on the valence band,making the valence band in InGaN well smoother,which not only reduces the height of the hole injection barrier,but also increases the hole concentration in InGaN well.The overlap integral of the electron-hole wave function in the well is also enhanced,and the probability of radiative recombination is improved,so the luminescence efficiency of the InGaN quantum well with the linear increase of In composition is significantly increased.