This paper reports a cathodoluminescence (CL) spectroscopic study of nanogranular AlNOErx samples with erbiumcontent, x, in the range 0.5--3.6 at%. A wide range of erbium concentration was studied with the aim ofunderstanding the concentration quenching of CL. The composition of thin films, deposited by radiofrequencyreactive magnetron sputtering, was accurately determined by Energy Dispersive X-ray Spectroscopy (EDS). CLemission was investigated in the extended visible spectral range from 350 nm to 850 nm. The critical concentrationof luminescent activator Er3+ above which CL quenching occurs is 1%; the corresponding criticaldistance between Er3+ ions in AlNOErx is about 1.0 nm. The quenching mechanism is discussed. We discount anexchange-mediated interaction in favour of a multipole-multipole phonon-assisted interaction.
Electron-beam Writing of Spectrally Uniform Green Single-photon Emitters in Hexagonal Boron Nitride
Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences（中国科学院大学杭州高等研究院）；Zhejiang University（浙江大学）；University of Science and Technology of China（中国科学技术大学）；Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences（中国科学院上海光学精密机械研究所）
Quantum-corrected thickness-dependent thermal conductivity in amorphous silicon predicted by machine-learning molecular dynamics simulations
非晶硅（a-Si）是一种重要的热管理材料，也是研究强无序材料热输运的理想场所。在很宽的温度和样品尺寸范围内理论预测a-Si的热导率仍然是一个挑战。在这里，我们提出了一个系统的研究a-Si的热输运性质，采用大规模的分子动力学（MD）模拟与准确和有效的机器学习神经进化潜力（NEP）训练对丰富的参考数据计算在量子力学密度泛函理论水平。NEP的高效率使我们能够非常详细地研究有限尺寸和淬火速率对a-Si形成的影响。我们发现，它需要一个模拟细胞$64,000$原子（立方细胞的线性尺寸为11 nm）和淬火速率下降到$10^{11}$ K s $^{-1}$完全收敛的热导率。结构性质，包括短程和中程秩序的特点是对关联函数，角分布函数，配位数，环统计和结构因子进行了研究，以证明NEP的准确性，并进一步评估淬灭率的作用。利用非均相和均相非平衡分子动力学方法以及相关的谱分解技术，计算了a-Si的热导率随温度和厚度的变化，结果表明，从10 K到室温，它们与已有的实验结果吻合得很好。我们的结果也突出了量子效应在计算热导率中的重要性，并支持了基于光谱热导率的量子校正方法。
