Amorphous/crystalline silicon heterojunction solar cells with black silicon texture

Excellent passivation of black silicon surfaces by thin amorphous silicon layers deposited with plasma enhanced chemical vapor deposition is demonstrated. Minority charge carrier lifetimes of 1.3 milliseconds, enabling an implied open‐circuit voltage of 714 mV, were achieved. The influence of amorphous silicon parasitic epitaxial growth and thickness, as well as of the texture depth is investigated. Furthermore, quantum efficiency gains for wavelengths above 600 nm, as compared to random textured solar cells, are demonstrated in 17.2% efficient amorphous–crystalline silicon heterojunction solar cells with black silicon texture. (© 2014 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

射频等离子硫钝化GaAs(100)的表面特性

采用射频等离子方法,对Ga As(100)衬底片表面进行干法硫等离子体钝化,旨在得到性能稳定含硫钝化层。样品经过360℃温度条件下的快速热退火,光致发光(PL)测试表明,钝化后的样品PL强度上升了71%。同时,钝化样品的稳定性测试结果表明,样品放置在实验室空气中30 d,其PL强度未出现明显变化,说明Ga As的等离子体干法硫钝化具有较好的性能稳定性。     

Trace determination of safranin O dye using ultrasound assisted dispersive solid-phase micro extraction: Artificial neural network-genetic algorithm and response surface methodology

In this study, ultrasound assisted dispersive solid-phase micro extraction combined with spectrophotometry (USA-DSPME-UV) method based on activated carbon modified with Fe₂O₃ nanoparticles (Fe₂O₃-NPs-AC) was developed for pre-concentration and determination of safranin O (SO). It is known that the efficiency of USA-DSPME-UV method may be affected by pH, amount of adsorbent, ultrasound time and eluent volume and the extent and magnitude of their contribution on response (in term of main and interaction part) was studied by using central composite design (CCD) and artificial neural network-genetic algorithms (ANN-GA). Accordingly by adjustment of experimental conditions suggested by ANN-GA at pH 6.5, 1.1 mg of adsorbent, 10 min ultrasound and 150 μL of eluent volume led to achievement of best operation performance like low LOD (6.3 ng mL⁻¹) and LOQ (17.5 ng mL⁻¹) in the range of 25–3500 ng mL⁻¹. In following stage, the SO content in real water and wastewater samples with recoveries between 93.27–99.41% with RSD lower than 3% was successfully determined.     

High-power high-stability Q-switched green laser with intracavity frequency doubling of diode-pumped composite ceramic Nd:YAG laser

We successfully obtain high-average-power high-stability Q-switched green laser based on diode-side-pumped composite ceramic Nd:YAG in a straight plano-concave cavity. The temperature distribution in composite ceramic Nd:YAG crystal is numerically analyzed and compared with that of conventional Nd:YAG crystal. By use of a composite ceramic Nd:YAG rod and a type-II high gray track resistance KTP (HGTR-KTP) crystal, a green laser with an average output power of 165 W is obtained at a repetition rate of 25 kHz, with a diode-to-green optical conversion of 14.68%, and a pulse width of 162 ns. To the best of our knowledge, both the output power and optical-to-optical efficiency are the highest values for green laser systems with intracavity frequency doubling of this novel composite ceramic Nd:YAG laser to date. The power fluctuation at around 160 W is lower than 0.3% in 2.5 hours.     

Ni、Co/AAO纳米有序阵列复合结构光吸收特性的比较研究

在多孔阳极氧化铝(AAO)模板中分别沉积金属镍(Ni)、钴(Co),制备了Ni／AAO和Co／AAO纳米有序阵列复合结构,对其光吸收特性进行了比较研究。实验结果表明．相同结构参量的模板中,Ni、Co纳米粒子的表观形状随沉积时间的变化规律基本一致．但Co/AAO及Ni／AAO复合结构的光吸收特性却有较大差异。Ni／AAO复合结构表现出间接带隙半导体的光学特征．而Co／AAO复合结构具有直接带隙半导体的光学特征。同时,随金属沉积量的增加,Ni／AAO吸收边的红移量仅约为13nm．而Co/AAO复合结构的吸收边红移量却超过了80nm。用Maxwell-Garnett(M-G)理论分析了导致二者光吸收特性存在较大差异的主要原因。     

Carbon nanotube-epoxy composites: The role of acid treatment in thermal and electrical conductivity

Wet acid oxidation treatment methods have been widely reported as an effective method to purify and oxidize the surface of industrial multi-walled carbon nanotubes. This work examines the use of a concentrated HNO₃/H₂SO₄ mixture in an attempt to optimize the purification procedure of industrial multi-walled carbon nanotubes with diameter distribution statistics. It is shown that acid treatments of several hours are enough to purify the nanotubes. The electrical and thermal conductivities of epoxy composites containing 0.05–0.25 wt% of an acid-treated multi-walled carbon nanotube have been studied. The electrical conductivity of the composites decreases by more than three orders, whereas the thermal conductivity of the same specimen increases very modestly as a function of the filler content.     

板条Nd:YAG晶体的合成盘抛光技术

针对高功率板条激光器核心工作器件——板条Nd:YAG晶体的超精密加工开展研究,分析了具有特殊构型的板条Nd:YAG晶体元件的加工性能及工艺难点,提出了一种新的基于合成盘抛光的板条Nd:YAG晶体加工工艺,并对规格为100mm×30mm×3mm的板条Nd:YAG晶体进行了加工实验。实验结果表明,合成盘抛光可以很好地控制元件的塌边现象;通过磨料的优化选择,在合成盘抛光工艺中匹配合适粒度的Al2O3磨料能够实现元件的低缺陷加工,元件下盘后的全反射面平面度达0.217λ(1λ=632.8nm),端面平面度达到0.06λ,表面粗糙度达0.55nm(RMS),端面楔角精度可达2″。     

ZnO/SiO2 复合薄膜的光学性能

采用溶胶-凝胶法在玻璃衬底上制备ZnO/SiO₂复合薄膜,分别用XRD、TEM、SEM对样品的结构和形貌进行表征,并研究了不同ZnO含量对复合薄膜透过率及荧光特性的影响。结果表明,样品经500 ℃退火处理生成了SiO₂和ZnO,其晶粒尺寸为18.7 nm,薄膜具有双层结构。复合薄膜的透过率随着其中ZnO含量的增加而降低,禁带宽度减小,光学吸收边红移。样品在355 nm波长激发下产生了384 nm的紫外发射峰和440 nm的蓝光发射带,并随ZnO含量的增加而增强,它们分别来自ZnO的电子-空穴复合发光和缺陷发光,及ZnO/SiO₂复合薄膜双层结构的缺陷发光。     

部分相干双曲正弦-Gauss涡旋光束叠加形成的合成相干涡旋在非 Kolmogorov 大气湍流中的动态演化

一些实验表明, 实际大气会偏离理想Kolmogorov模型. 本文基于广义Huygens-Fresnel原理和Toselli等提出的非Kolmogorov湍流模型, 推导出部分相干双曲正弦-Gauss (HSG)涡旋光束通过非Kolmogorov大气湍流的解析传输公式, 并用以对两束部分相干HSG涡旋光束相干叠加和非相干叠加形成的合成相干涡旋在非Kolmogorov大气湍流中的动态演化进行了研究. 结果表明, 合成光束平均光强的演化过程与非Kolmogorov湍流的广义指数α, 源平面上叠加涡旋光束拓扑电荷的符号, 以及叠加方式有关. 合成相干涡旋在非Kolmogorov大气湍流中传输时会出现移动、产生和湮灭. 广义指数α, 拓扑电荷符号, 以及叠加方式都会影响其演化行为. 最后, 将本文所得结果与相关文献做了比较.