Zhao Xiaoyu, Wan Zehong, Gong Liyan, Tao Guoyi, Zhou Shengjun
Center for Photonics and Semiconductors, School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China.
The Institute of Technological Sciences, Wuhan University, Wuhan 430072, China.
Nanomaterials (Basel). 2021 Nov 28;11(12):3231. doi: 10.3390/nano11123231.
InGaN-based long-wavelength light-emitting diodes (LEDs) are indispensable components for the next-generation solid-state lighting industry. In this work, we introduce additional InGaN/GaN pre-wells in LED structure and investigate the influence on optoelectronic properties of yellow (~575 nm) LEDs. It is found that yellow LED with pre-wells exhibits a smaller blue shift, and a 2.2-fold increase in light output power and stronger photoluminescence (PL) intensity compared to yellow LED without pre-wells. The underlying mechanism is revealed by using Raman spectra, temperature-dependent PL, and X-ray diffraction. Benefiting from the pre-well structure, in-plane compressive stress is reduced, which effectively suppresses the quantum confined stark effect. Furthermore, the increased quantum efficiency is also related to deeper localized states with reduced non-radiative centers forming in multiple quantum wells grown on pre-wells. Our work demonstrates a comprehensive understanding of a pre-well structure for obtaining efficient LEDs towards long wavelengths.
基于氮化铟镓的长波长发光二极管（LED）是下一代固态照明产业不可或缺的组件。在这项工作中，我们在LED结构中引入额外的氮化铟镓/氮化镓预阱，并研究其对黄色（~575 nm）LED光电特性的影响。研究发现，与没有预阱的黄色LED相比，带有预阱的黄色LED表现出更小的蓝移，光输出功率增加了2.2倍，光致发光（PL）强度更强。通过拉曼光谱、温度相关的PL和X射线衍射揭示了其潜在机制。受益于预阱结构，面内压应力降低，有效抑制了量子限制斯塔克效应。此外，量子效率的提高还与预阱上生长的多量子阱中形成的非辐射中心减少且局域态更深有关。我们的工作展示了对预阱结构的全面理解，有助于获得高效的长波长LED。
