Jiang Cheng, Wang Hongpei, Chen Hongmei, Dai Hao, Zhang Ziyang, Li Xiaohui, Yao Zhonghui
School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei 230026, China.
School of Electronic and Information Engineering, Qingdao University, Qingdao 266071, China.
Nanomaterials (Basel). 2022 Apr 22;12(9):1431. doi: 10.3390/nano12091431.
Semiconductor superluminescent light-emitting diodes (SLEDs) have emerged as ideal and vital broadband light sources with extensive applications, such as optical fiber-based sensors, biomedical sensing/imaging, wavelength-division multiplexing system testing and optoelectronic systems, etc. Self-assembled quantum dots (SAQDs) are very promising candidates for the realization of broadband SLED due to their intrinsic large inhomogeneous spectral broadening. Introducing excited states (ESs) emission could further increase the spectral bandwidth. However, almost all QD-based SLEDs are limited to the ground state (GS) or GS and first excited state (ES) emission. In this work, multiple five-QD-layer structures with large dot size inhomogeneous distribution were grown by optimizing the molecular beam epitaxy (MBE) growth conditions. Based on that, with the assistance of a carefully designed mirror-coating process to accurately control the cavity mirror loss of GS and ESs, respectively, a broadband QD-SLED with three simultaneous states of GS, ES and second excited-state (ES) emission has been realized, exhibiting a large spectral width of 91 nm with a small spectral dip of 1.3 dB and a high continuous wave (CW) output power of 40 mW. These results pave the way for a new fabrication technique for high-performance QD-based low-coherent light sources.
半导体超发光发光二极管（SLED）已成为理想且至关重要的宽带光源，具有广泛应用，如基于光纤的传感器、生物医学传感/成像、波分复用系统测试及光电子系统等。自组装量子点（SAQD）因其固有的大非均匀光谱展宽，是实现宽带SLED非常有前景的候选材料。引入激发态（ES）发射可进一步增加光谱带宽。然而，几乎所有基于量子点的SLED都局限于基态（GS）或GS与第一激发态（ES）发射。在这项工作中，通过优化分子束外延（MBE）生长条件，生长出具有大尺寸量子点非均匀分布的多个五量子点层结构。在此基础上，借助精心设计的镜面镀膜工艺分别精确控制GS和ES的腔镜损耗，实现了一种具有GS、ES和第二激发态（ES）发射三种同时存在状态的宽带量子点SLED，其光谱宽度达91 nm，光谱凹陷小至1.3 dB，连续波（CW）输出功率高达40 mW。这些结果为高性能基于量子点的低相干光源的新制造技术铺平了道路。
