240 nm AlGaN-based micro-LEDs with different sizes are designed and fabricated. Then, the external quantum efficiency (EQE) and light extraction efficiency (LEE) are systematically investigated by comparing size and edge effects. Here, it is revealed that the peak optical output power increases by 81.83% with the size shrinking from 50.0 to 25.0 μm. Thereinto, the LEE increases by 26.21% and the LEE enhancement mainly comes from the sidewall light extraction. Most notably, transverse-magnetic (TM) mode light intensifies faster as the size shrinks due to the tilted mesa side-wall and Al reflector design. However, when it turns to 12.5 μm sized micro-LEDs, the output power is lower than 25.0 μm sized ones. The underlying mechanism is that even though protected by SiO₂ passivation, the edge effect which leads to current leakage and Shockley-Read-Hall (SRH) recombination deteriorates rapidly with the size further shrinking. Moreover, the ratio of the p-contact area to mesa area is much lower, which deteriorates the p-type current spreading at the mesa edge. These findings show a role of thumb for the design of high efficiency micro-LEDs with wavelength below 250 nm, which will pave the way for wide applications of deep ultraviolet (DUV) micro-LEDs.

岩石力学性质参数具有尺寸效应，这一重要性质在工程设计和建设中往往被忽略。进行不同尺寸岩石的力学性质实验是研究岩石材料尺寸效应的主要方法，但是目前的实验规程缺少针对不同尺寸试样的实验方法，并且缺少非标准尺寸试样的配套实验夹具装置。该文提出了岩石尺寸效应实验的试样制备标准，设计了配套的实验夹具装置，完善了岩石尺寸效应实验方法。选取白砂岩为研究对象开展抗压和抗拉强度尺寸效应实验，研究岩石力学参数与试样尺寸之间的关系。结果表明，岩石抗压强度和变形模量随着试样尺寸的增加而减小，泊松比没有尺寸效应规律，抗拉强度先增大后减小。

Micro LED技术作为下一代显示技术的前沿研究领域，具备高亮度、高对比度和高能效等优势。回顾了Micro LED技术的发展历程，重点介绍了其技术难点以及当前的进展情况。技术难点包括外延结构设计、芯片制备中的尺寸效应、全彩化问题、Micro LED系统集成和可靠性研究。当前的进展涵盖了侧壁效应抑制、全彩化方案、巨量转移技术、氮化物红光技术、色转换技术、垂直堆叠技术、CMOS和TFT驱动、三维集成技术、透明显示以及纳米LED。最后展望了Micro LED技术的未来发展方向，包括解决技术难题、推动产业化进程和实现更广泛的应用。

Topological edge states (TESs), arising from topologically nontrivial phases, provide a powerful toolkit for the architecture design of photonic integrated circuits, since they are highly robust and strongly localized at the boundaries of topological insulators. It is highly desirable to be able to control TES transport in photonic implementations. Enhancing the coupling between the TESs in a finite-size optical lattice is capable of exchanging light energy between the boundaries of a topological lattice, hence facilitating the flexible control of TES transport. However, existing strategies have paid little attention to enhancing the coupling effects between the TESs through the finite-size effect. Here, we establish a bridge linking the interaction between the TESs in a finite-size optical lattice using the Landau–Zener model so as to provide an alternative way to modulate/control the transport of topological modes. We experimentally demonstrate an edge-to-edge topological transport with high efficiency at telecommunication wavelengths in silicon waveguide lattices. Our results may power up various potential applications for integrated topological photonics.

钙锆共掺钛酸钡陶瓷(BCZT)具有优异的介电性能和压电性能, 是一类具有发展潜力的无铅压电陶瓷, 但其压电性能仍无法与铅基陶瓷媲美。为提高压电性能, 本研究对陶瓷材料进行Sn元素掺杂改性((Ba_0.85Ca_0.15)- (Ti_0.9Zr_0.1-xSn_x)O₃, x=0.02~0.07))。晶体结构分析证实所有组分的陶瓷无杂相, 处于正交相与四方相两相共存状态, 并具有较大的c/a; 显微结构分析发现所有陶瓷都很致密, 且平均晶粒尺寸随着Sn含量的增加而增大。当x=0.04时, 陶瓷最致密, 且室温处于准同型相界附近, 因此拥有最佳的电学性能: d₃₃=590 pC•N ^-1, k_p=52.2%, tanδ=0.016, ε ^T₃₃=5372, d ^*₃₃=734 pm•V ^-1, IR=57.8 GΩ•cm。本研究表明: Sn掺杂的BCZT基无铅压电陶瓷具有优异的压电性能, 有望在换能器、机电传感器和驱动器等方面得到应用。