The development of an efficient group-IV light source that is compatible with the CMOS process remains a significant goal in Si-based photonics. Recently, the GeSn alloy has been identified as a promising candidate for realizing Si-based light sources. However, previous research suffered from a small wafer size, limiting the throughput and yield. To overcome this challenge, we report the successful growth of GeSn/Ge multiple-quantum-well (MQW) p-i-n LEDs on a 12-inch (300-mm) Si substrate. To the best of our knowledge, this represents the first report of semiconductor LEDs grown on such a large substrate. The MQW LED epitaxial layer is deposited on a 12-inch (300-mm) (001)-oriented intrinsic Si substrate using commercial reduced pressure chemical vapor deposition. To mitigate the detrimental effects of threading dislocation densities on luminescence, the GeSn/Ge is grown pseudomorphically. Owing to the high crystal quality and more directness in the bandgap, enhanced electroluminescence (EL) integrated intensity of 27.58 times is demonstrated compared to the Ge LED. The MQW LEDs exhibit EL emission near 2 μm over a wide operating temperature range of 300 to 450 K, indicating high-temperature stability. This work shows that GeSn/Ge MQW emitters are potential group-IV light sources for large-scale manufacturing.

Different from single and static photonic materials, dynamically responsive materials possess numerous advantages, such as being multifunctional, dynamically responsive, and able to provide multiple channels within spatially limited platforms, thus exhibiting great potential for application in the color-on-demand areas, including imaging, optical displays, anticounterfeiting, and encoding. Photonic functional metal–organic frameworks (MOFs), with highly designable framework structures and varieties of optical functional building units, possess broad research and application prospects in the field of photonics, which make it possible to design a promising platform with multifunctional and integrated photonic performance. In this review, beyond the preparation strategies of stimuli-responsive photonic MOFs, we also summarize the stimuli-responsive photonic MOFs regarding several most representative types of external stimuli (such as light, gas, pressure, and polarization). As shown, external stimulation endows the stimuli-responsive photonic MOFs with intriguing regulatable photonic properties: intensive and tunable emission, multiphoton-excitable luminescence, nonlinear optical, circularly polarized luminescence, lasing, etc. Furthermore, their advanced representative applications, such as information encryption and anticounterfeiting display, biological imaging, chemosensing, and others, are also reviewed. The challenges are proposed and the prospects are addressed.

时间分辨X射线吸收精细结构谱技术需要产生高亮度、均匀、宽光谱的X射线源。单一靶材产生的M带辐射源亮度高，但均匀性较差，因此提出了一种使用多种金属材料制备的多层膜复合靶产生M带辐射的方案。针对Si的K边X射线吸收谱实验，根据前期单一靶材M带光谱实验数据理论计算了最优的材料比例，制备了Au、Yb、Dy三种材料组成的多层膜复合靶，并在神光II激光装置上开展了脉冲激光驱动的多层膜复合靶辐射光谱测量，实验结果和理论计算基本一致。相比单一靶材，多层膜复合靶产生的M带辐射源具有光谱宽、整体亮度均匀的优点，在时间分辨X射线吸收精细结构谱中具有较大的应用潜力。

伪装效果评估是伪装技术发展的重要内容。为了充分利用光谱细节信息对目标高光谱伪装效果进行评价，提出了基于光谱指数的伪装效果评估方法，该方法兼具可视化和量化分析的优势。可视化方面，通过光谱指数对高光谱图像进行阈值分割，实现目视解译的伪装效果评估；量化分析方面，以现有的遥感光谱指数为基础，构建新的伪装光谱指数来量化目标与背景的光谱特征，并提出光谱一致性系数指标，将各谱段的光谱指数加权综合进而量化评估目标伪装效果。实验结果表明：该方法的评估结果能够有效辨识目标伪装前后的高光谱伪装效果，且在传统指标相似度达到99%以上时，本文方法仍能有效辨识目标并给出客观评价，其在单个谱段的一致性以及宽谱段的整体匹配性方面评估结果更精准全面，更科学合理。