稀土配合物掺杂的中孔杂化发光材料的制备及其表征

稀土配合物由于具有优良的窄带发光性能和较长的荧光寿命，因而在光电学领域比如激光材料或者荧光标记上引起了广泛的兴趣和应用。吸附在固体表面的稀土配合物的发光性质得到了广泛的研究。MCM-48中孔材料是M41S家族中的一种，具有直径20-30A三维结构的中孔孔道，比MCM-41的一维结构孔道更有优势，比如它可以最大可能的避免客体分子的堆积现象。因此本论文中我们研究了将稀土（Eu3+）β-二酮（DBM＝dibenzoylmethane）配合物掺杂到纯硅MCM-48以及三种有机基团嫁接的有机－无机杂化MCM-48的孔道中去，得到了各种不同的杂化中孔发光材料。首先烧结后的MCM-48被装载稀土Eu（OBM）3'2H2O配合物之后。XRD结果说明稀土配合物被组装到了MCM-48中，其有序结构因为稀土配合物的进入而受到一定的影响，但是样品仍保持了MCM-48的立方相结构。分别通过吸收光谱和热失重的方法计算了掺杂后的发光MCM-48样品进行洗涤后留在MCM一48中配合物的量。固体漫反射光谱在紫外区有一个OBM配体的Sn基态能级（π）到S1激发态能级份＊）的电子跃迁形成的吸收宽带。可见区还观察到E护”离子的4f-4畴征吸收线。与稀土配合物中的OBM配体相比，掺杂MCM-48样品的Sn-S1吸收带均发生蓝移，反映了S1能级向高能方向移动。然后采用了室温两步合成法合成MCM-48，模板剂的去除采用了溶剂萃取法。最佳掺杂浓度为6.98×10-3 mol/l；同时最佳掺杂时间为24小时。在同样的掺杂条件下，稀土配合物在基质中的掺杂量MCM-48＞MCM-41＞＞SiO2。萃取之后的MCM-48在外形上近乎于球形，粒子的直径在0.7-1.2μm之间。粒子显现出多孔的海绵状表面形态，并且具有晶体结构外形，呈菱形十二面体被削去顶端立方体的结构。而且在粒子的表面观察到了类似螺旋结构的孔道，我们认为这是MCM一48所特有的双螺旋型三维孔道结构，这是到目前为止首次报道利用扫描电镜观察到中孔分子筛的孔道结构。荧光光谱结果观察到了激发峰的最大值由于纳米粒子效应出现的蓝移现象。不同基质中的发射系数QZ和04比较可知配合物在三种基质SiO2、MCM-41和MCM-48中环境的极性相差不大。掺杂到中孔MCM-48材料中的稀土配合物的热稳定性比在MCM-41中强，这是由于MCM-48的三维孔道对配合物的保护作用。室温条件下合成的MCM-48分子筛利用后合成嫁接的方法[post-synthesis grajng（PSG）]进行表面修饰，修饰剂选用了带有功能性乙烯基的VTES，链长最短的MTES以及带有氨基的长链NTSED。稀土Eu（DBM）3'2H2O配合物被组装到杂化中孔分子筛材料中。红外光谱与2951核磁共振光谱表明MCM-48的表面被成功的接枝上了有机M下任S，盯任s，N丁s任D基团。与MCM-48相比，MCM-48-R的表面积、孔体积和孔径的减少有以下NTSED＞VTES＞MTES的顺序。这也许是修饰的有机基团不同的链的长度不同的原因。稀土配合物在这三种有机一无机杂化基质环境的极性比纯硅MCM-48要增大。同时配合物在三种基质的中的QZ的值及发光效率的顺序为：MCM-48-MTES＜MCM-48-VTES＜MCM-48-NTSED，说明MCM-48经过三种有机硅氧烷修饰之后孔道极性也遵循同样的顺序，可以认为这是由于三种有机基团的链长的不同造成的，链长越长则修饰之后孔道极性增大的就越多。最后通过溶胶一凝胶过程利用提拉法（Dip-coating method）制备了具有中孔结构的SiO2-CTAB-Tb（acac）3透明发光薄膜（Mesostructed Iuminescence thin film，略为MLTF），稀土配合物利用原位合成（In-situ）的办法掺入到透明薄膜中。对薄膜进行热处理过程表明薄膜中的稀土配合物在50℃的时候开始形成。XRO结果表明稀土离子及有机配体的掺入对薄膜中孔相的结构没有太大的影响，荧光薄膜仍保持层状结构。红外光谱结果说明制备的中孔薄膜是由CTAB和硅氧烷聚合物组成的复合薄膜。荧光薄膜的发射光谱给出了Th3+离子的特征发射峰，荧光薄膜中有机配体与丁b离子之间发生了能量传递现象。因为在热处理过程中有机配体逐渐代替了开始与Tb离子配位的OH基团，使得二者间的能量传递更加有效，从而导致了荧光的增强。

A Hybrid Random Number Generator Using Single Electron Tunneling Junctions and MOS Transistors

This paper proposes a novel single electron random number generator (RNG). The generator consists of multiple tunneling junctions (MTJ) and a hybrid single electron transistor (SET)/MOS output circuit. It is an oscillator-based RNG. MTJ is used to implement a high-frequency oscillator,which uses the inherent physical randomness in tunneling events of the MTJ to achieve large frequency drift. The hybrid SET and MOS output circuit is used to amplify and buffer the output signal of the MTJ oscillator. The RNG circuit generates high-quality random digital sequences with a simple structure. The operation speed of this circuit is as high as 1GHz. The circuit also has good driven capability and low power dissipation. This novel random number generator is a promising device for future cryptographic systems and communication applications.

A Novel Three-Section Self-Pulsating DFB Laser with Hybrid Grating

A 1.55μm InGaAsP-InP three-section DFB laser with hybrid grating is fabricated and self-pulsations (SP) with frequencies around 20GHz are observed. The mechanism of SP generation in this device is researched. Furthermore, the important role of the phase tuning section on the SP is investigated.

Photonic AND Gate Based on Hybrid Integration of GaAs VCSEL and GaAs MISS

于2010-11-23批量导入

Hybrid CMOS/VCSEL optoelectronic modules

We report some investigations on vertical cavity surface emitting laser (VCSEL) arrays and VCSEL based optoelectronic smart photonic multiple chip modules (MCM), consisting of 1x16 vertical cavity surface emitting laser array and 16-channel lasers driver 0.35 Pin CMOS circuit. The hybrid integrated multiple chip modules based on VCSEL operate at more than 2GHz in -3dB frequency bandwidth.

Growth and fabrication of high performance 980nm strained InGaAs quantum well lasers using novel hybrid material system of InGaAsP and AlGaAs

In this paper, we report on the design, growth and fabrication of 980nm strained InGaAs quantum well lasers employing novel material system of Al-free active region and AlGaAs cladding layers. The use of AlGaAs cladding instead of InGaP provides potential advantages in laser structure design, improvement of surface morphology and laser performance. We demonstrate an optimized broad-waveguide structure for obtaining high power 980nm quantum well lasers with low vertical beam divergence. The laser structure was grown by low-pressure metalorganic chemical vapor deposition, which exhibit a high internal quantum efficiency of similar to 90% and a low internal loss of 1.5-2.5 cm(-1). The broad-area and ridge-waveguide laser devices are both fabricated. For 100 mu m wide stripe lasers with cavity length of 800 mu m, a low threshold current of 170mA, a high slope efficiency of 1.0W/A and high output power of more than 3.5W are achieved. The temperature dependences of the threshold current and the emitting spectra demonstrate a very high characteristic temperature coefficient (T-o) of 200-250K and a wavelength shift coefficient of 0.34nm/degrees C. For 4 mu m-width ridge waveguide structure laser devices, a maximum output power of 340mW with GOD-free thermal roll-over characteristics is obtained.

Flip-chip bonded hybrid CMOS/SEED optoelectronic smart pixels

Hybrid integration of GaAs/AlGaAs multiple quantum well self electro-optic effect device (SEED) arrays are demonstrated flip-chip bonded directly onto 1 mu m silicon CMOS circuits. The GaAs/AlGaAs MQW devices are designed for 850 nm operation. Some devices are used as input light detectors and others serve as output light modulators. The measurement results under applied biases show good optoelectronic characteristics of elements in SEED arrays. Nearly the same reflection spectrum is obtained for the different devices at an array and the contrast ratio is more than 1.2:1 after flip-chip bonding and packaging. The transimpedance receiver-transmitter circuit can be operated at a frequency of 300 MHz.

Hybrid waveguide-plasmon resonances in gold pillar arrays on top of a dielectric waveguide

We propose a hybrid waveguide-plasmon system consisting of gold pillar arrays on top of a dielectric waveguide. The formation of extraordinary transmissions induced by the hybrid waveguide-plasmon resonances is investigated by rigorous coupled-wave analysis. The characteristics of the hybrid resonances can be predicted by introducing the photonic crystal slab theory. Extremely narrow absorption peaks and the electromagnetically induced transparency-like optical property are demonstrated in our hybrid system. (C) 2010 Optical Society of America

Improved digital processing method used for image motion measurement based on hybrid opto-digital joint transform correlator

Hybrid opto-digital joint transform correlator (HODJTC) is effective for image motion measurement, but it is different from the traditional joint transform correlator because it only has one optical transform and the joint power spectrum is directly input into a digital processing unit to compute the image shift. The local cross-correlation image can be directly obtained by adopting a local Fourier transform operator. After the pixel-level location of cross-correlation peak is initially obtained, the up-sampling technique is introduced to relocate the peak in even higher accuracy. With signal-to-noise ratio >= 20 dB, up-sampling factor k >= 10 and the maximum image shift <= 60 pixels, the root-mean-square error of motion measurement accuracy can be controlled below 0.05 pixels.