基于密度泛函理论（Density Functional Theory，DFT）研究了锕系元素铀（U）、钍（Th）、钚（Pu）在二维金属材料锑烯表面的吸附特性。采用线性响应法拟合得到描述铀、钚5f轨道电子强格点库仑作用的哈伯德U值分别为2.24 eV和2.84 eV。利用DFT+U计算发现，锑烯难以吸附钚原子（吸附能为负值），而对铀、钍原子具有较强的表面化学吸附以及丰富的稳定吸附位点。铀和钍原子能量上最稳定的吸附位点分别为桥位——孔位之间和孔位，吸附能分别为4.40 eV和3.62 eV。通过电子结构、电荷转移和最高占据态轨道波函数分析发现，铀、钍原子使锑烯的带隙中出现杂质态，并与锑烯之间通过强p-d轨道耦合使其稳定吸附。进一步计算了吸附率随温度的变化，得出铀和钍在锑烯表面的解吸温度分别达到837 K和660 K。结果预示锑烯是一种良好的铀、钍吸附材料，在海水提铀等领域具有潜在应用。

Semipolar III-nitrides have attracted increasing attention in applications of optoelectronic devices due to the much reduced polarization field. A high-quality semipolar AlN template is the building block of semipolar AlGaN-based deep-ultraviolet light emitting diodes (DUV LEDs), and thus deserves special attention. In this work, a multi-step in situ interface modification technique is developed for the first time, to our knowledge, to achieve high-quality semipolar AlN templates. The stacking faults were efficiently blocked due to the modification of atomic configurations at the related interfaces. Coherently regrown AlGaN layers were obtained on the in situ treated AlN template, and stacking faults were eliminated in the post-grown AlGaN layers. The strains between AlGaN layers were relaxed through a dislocation glide in the basal plane and misfit dislocations at the heterointerfaces. In contrast, high-temperature ex situ annealing shows great improvement in defect annihilation, yet suffers from severe lattice distortion with strong compressive strain in the AlN template, which is unfavorable to the post-grown AlGaN layers. The strong enhancement of luminous intensity is achieved in in situ treated AlGaN DUV LEDs. The in situ interface modification technique proposed in this work is proven to be an efficient method for the preparation of high-quality semipolar AlN, showing great potential towards the realization of high-efficiency optoelectronic devices.

微透镜阵列是一种被广泛应用于光信息处理、光传感、光计算、光通信和高灵敏度成像等领域的精密光学元器件之一。通过一些先进的制造技术已经可以制造出不同几何形状、轮廓和光学特性的微透镜阵列。然而，由于三维微制造工艺的难度，使得高填充因子微透镜阵列中的微透镜很难实现紧密排列。提出了一种快速、低成本的微流体操纵技术，用于制备高填充因子微透镜阵列，且对其制备工艺进行了初步的演示。这种易于操作的制造技术适用于微透镜阵列的大批量生产，极大地提高了生产效率。通过预先制备出的三种不同尺寸(微柱直径分别为300、500、700 μm)的微柱，实现了与其对应不同形状和尺寸的微透镜阵列的制备，并搭建了一套光学成像系统以对这些微透镜阵列进行成像性能的评估。主要对微透镜阵列的焦距、成像精度和每个微透镜阵列中各个微透镜子单元成像的均一性进行测试，利用所提出的微流体操控技术制备的微透镜阵列具有良好的成像性能，有望能够被应用到三维成像、光均匀化等诸多应用中。

A straightforward, cost-effective scheme for fabricating multi-focus droplet lens arrays is proposed. Mini lenses can be rapidly produced by dripping liquid-state polydimethylsiloxane droplets on the square glass substrate. The focal length of the lenses can be precisely controlled by adjusting the mass of the droplet. A group of prepared mini lenses can be flexibly assembled in a three-dimensional printed mount. The lenses are tightly packed together, ensuring a high filling factor of the lens array. The lens array consisting of the mini lenses with a proper combination of focal length can capture images of interests at different depth.

AlGaN-based solid state UV emitters have many advantages over conventional UV sources. However, UV-LEDs still suffer from numerous challenges, including low quantum efficiency compared to their blue LED counterparts. One of the inherent reasons is a lack of carrier localization effect inside fully miscible AlGaN alloys. In the pursuit of phase separation and carrier localization inside the active region of AlGaN UV-LED, utilization of highly misoriented substrates proves to be useful, yet the carrier distribution and recombination mechanism in such structures has seldom been reported. In this paper, a UV-LED with step-bunched surface morphology was designed and fabricated, and the internal mechanism of high internal quantum efficiency was studied in detail. The correlation between microscale current distribution and surface morphology was provided, directly demonstrating that current prefers to flow through the step edges of the epitaxial layers. Experimental results were further supported by numerical simulation. It was found that efficient radiative recombination centers were formed in the inclined quantum well regions. A schematic three-dimensional energy band structure of the multiple quantum wells (MQWs) across the step was proposed and helps in further understanding the luminescence behavior of LEDs grown on misoriented substrates. Finally, a general principle to achieve carrier localization was proposed, which is valid for most ternary III-V semiconductors exhibiting phase separation.