Kim Sang-Jo, Oh Semi, Lee Kwang-Jae, Kim Sohyeon, Kim Kyoung-Kook
School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea.
Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI 48109, USA.
Micromachines (Basel). 2021 Apr 5;12(4):399. doi: 10.3390/mi12040399.
We demonstrate the highly efficient, GaN-based, multiple-quantum-well light-emitting diodes (LEDs) grown on Si (111) substrates embedded with the AlN buffer layer using NH growth interruption. Analysis of the materials by the X-ray diffraction omega scan and transmission electron microscopy revealed a remarkable improvement in the crystalline quality of the GaN layer with the AlN buffer layer using NH growth interruption. This improvement originated from the decreased dislocation densities and coalescence-related defects of the GaN layer that arose from the increased Al migration time. The photoluminescence peak positions and Raman spectra indicate that the internal tensile strain of the GaN layer is effectively relaxed without generating cracks. The LEDs embedded with an AlN buffer layer using NH growth interruption at 300 mA exhibited 40.9% higher light output power than that of the reference LED embedded with the AlN buffer layer without NH growth interruption. These high performances are attributed to an increased radiative recombination rate owing to the low defect density and strain relaxation in the GaN epilayer.
我们展示了一种高效的、基于氮化镓（GaN）的多量子阱发光二极管（LED），该器件生长在嵌入了氮化铝（AlN）缓冲层的硅（Si）（111）衬底上，采用了NH生长中断技术。通过X射线衍射ω扫描和透射电子显微镜对材料进行分析，结果表明，使用NH生长中断技术的含AlN缓冲层的GaN层的晶体质量有了显著提高。这种改善源于GaN层位错密度的降低以及由于Al迁移时间增加而产生的与合并相关的缺陷的减少。光致发光峰值位置和拉曼光谱表明，GaN层的内部拉伸应变得到了有效弛豫，且未产生裂纹。在300 mA电流下，采用NH生长中断技术嵌入AlN缓冲层的LED的光输出功率比未采用NH生长中断技术嵌入AlN缓冲层的参考LED高出40.9%。这些高性能归因于GaN外延层中缺陷密度低和应变弛豫导致的辐射复合率增加。
