复合成核层对InGaN基黄光LED内量子效率的影响

Effect of Hybrid Nucleation Layer on Internal Quantum Efficiency of InGaN-based Yellow LEDs

开发了一种由溅射AlN层和中温GaN层组成的复合成核层来提高黄光LED的内量子效率。系统地研究了在溅射AlN成核层和复合成核层上生长的InGaN基黄光LED的晶体质量和光学性能,揭示了复合成核层对黄光LED内量子效率的影响机制。分别采用透射电子显微镜、X射线衍射、拉曼光谱、变温光致发光谱和电致发光谱对黄光LED进行表征分析。结果发现,复合成核层能够诱导产生堆垛层错,可以有效降低外延层中的位错密度和残余应力。在溅射AlN成核层和复合成核层上生长的黄光LED外延层中的位错密度分别为5.04×10^(8) cm^(-2)和3.98×10^(8) cm^(-2),压应力分别为482.71 MPa和266.38 MPa。通过变温光致发光谱计算得到在溅射AlN成核层和复合成核层上生长的黄光LED的内量子效率(室温295 K)分别为12.5%和29.8%。

A hybrid nucleation layer consisting of sputtered AlN component and mid-temperature GaN component was developed to improve the internal quantum efficiency of yellow LED.Transmission electron microscopy,X-ray diffraction,and Raman spectra were used to characterize the crystal quality of InGaN-based yellow LEDs.The optical properties of InGaN-based yellow LEDs were investigated by temperature-dependent photoluminescence spectra and electroluminescence spectra.It is found that stacking faults are formed using the hybrid nucleation layer,which can effectively reduce the dislocation density and residual stress in the epitaxial layer.The dislocation density of yellow LED epitaxial layer grown on the sputtered AlN nucleation layer and hybrid nucleation layer is 5.04×10^(8 )cm^(-2) and 3.98×10^(8) cm^(-2).The in-plane compressive stress of yellow LED grown on the sputtered AlN nucleation layer and hybrid nucleation layer is 482.71 MPa and 266.38 MPa.By replacing the conventional sputtered AlN nucleation layer with hybrid nucleation layer,the internal quantum efficiency of yellow LEDs is increased from 12.5%to 29.8%at room temperature of 295 K.