Spectroscopic investigations on Er3+/Yb3+-doped oxyfluoride glass ceramics containing YOF nanocrystals

Spectroscopic properties of Er3+/Yb3+-doped transparent oxyfluoride borosilicate glass ceramics containing YOF nanocrystals were systematically investigated. X-ray diffraction (XRD) confirmed the formation of YOF nanocrystals in the glassy matrix. Based on the Judd-Ofelt theory, the intensity parameters Ωi (i=2, 4, 6), spontaneous emission probability, radiative lifetime, radiative quantum efficiency and the effective emission bandwidth were investigated. The upconversion luminescence intensity of Er3+ ions in the glass ceramics increased significantly with the increasing crystallization temperature. The transition mechanisms of the green and red upconversion luminescence were ascribed to a two-photon process, and the blue upconversion luminescence was a three-photon absorption process.     

卫星遥感全天候监测海雾技术与应用

运用光谱分析法和结构分析法以及相应的处理技术,进行了云雾自动检测和分离技术的研究和应用研究,在此基础上,系统阐明了全天候海雾遥感监测系统的设计原则与流程框架,并利用GMS5和NOAA卫星的可见光和红外通道资料,对2001年4月17、18日的黄海海雾进行了个例监测实验,取得了较为理想的海雾监测结果。     

二氧化锆栅介质薄膜光学及电学特性研究

采用反应RF磁控溅射法在氧气和氩气的混合气氛中制备了具有较高介电常数、较宽光学禁带间隙的ZrO2薄膜。利用变角度光谱椭圆偏振仪研究了不同O2/Ar流量比下制备所得薄膜的厚度、复折射率、复介电常数和吸收系数,估算了薄膜的光学禁带间隙,并测试分析了在不同O2/Ar流量比下溅射沉积的Al/ZrO2/SiO2/n型Si叠层结构的C V、I V特性曲线。通过对O2/Ar流量比分别为1/9、1/4、4/1、1/0工艺条件下溅射沉积ZrO2薄膜的α2与光子能量关系图的拟合,确定了其光学禁带间隙Eg分别为6.27、5.84、6.03、5.92eV,在O2/Ar流量比为1/9、1/4、1/0工艺条件下溅射沉积ZrO2薄膜,其ZrO2/SiO2叠层的有效介电常数keff计算结果分别为14.6、19.6和9.3,漏电流较低(<5.0×10-5A/cm2),其击穿电场强度分别为5.6、6.3、9MV/cm。     

In situ ellipsometric study of copper growth on silicon

Thin copper films are of high interest for interconnect applications. However, optical studies, such as ellipsometry, of metallic thin films are still rare as the measurements are difficult to interpret due to the lack of a transparent range and often island-like growth at very low coverages. We investigated by in situ spectroscopic ellipsometry the growth of thermally evaporated thin copper films on silicon substrates from 0.5 nm to more than 100 nm, a thickness for which bulk-like response is observed. A strong change in the optical response was observed for films thinner than 10 nm as a result of plasmonic effects. The data at each thickness was modeled by employing the effective medium approximation theory. Besides the layer thickness and the void filling fraction, giving the film density, we obtained information about the mean free path of electrons in the thin films and compared it to single crystals. Cu oxidation was studied by deliberately introducing oxygen or air in the chamber, leading to a fast and pronounced change in the optical response. The data analysis provides detailed information on film thickness and quality.     

浮法玻璃表面光学常数分析

本文通过光谱椭偏仪测量浮法玻璃空气面和锡面的偏振信息,利用Cauchy光学模型分析得到浮法玻璃两表面的布鲁斯特角和光学常数,分析结果表明浮法玻璃空气面、锡面、理想玻璃界面的布鲁斯特角分别为56.7°、57°和56.8°,空气面形成疏松的表面层,厚度为2.75nm,折射率小于玻璃本底,锡面形成锡扩散表面层,厚度为81.29nm,折射率大于玻璃本底折射率,并且随厚度呈现出非线性梯度变化,结合透光率数据分析得到玻璃消光系数在10-6量级。由于浮法玻璃空气面和锡面的折射率明显不同,需要在后续玻璃镀膜光学设计时区别对待。     

Intense upconversion luminescence of Er3+/Yb3+ codoped oxyfluoride borosilicate glass ceramics containing Ba2GdF7 nanocrystals

Er3+/Yb3+-codoped transparent oxyfluoride borosilicate glass ceramics containing Ba2GdF7 nanocrystals were prepared and spectroscopic properties of rare earth ions were investigated.Fluoride nanocrystals Ba2GdF7 were successfully precipitated in glass matrix,which was confirmed by X-ray diffraction(XRD)and transmission electron microscopy(TEM)results.In comparison with the as-made precursor,significant enhancement ofupconversion luminescence was observed in the Er3+/Yb3+codoped oxyfluoride glass ceramics,which may be due to the variation of coordination environment around Er3+and Yb3+ions after crystallization.The transition mechanisms of the green and red upconversion luminescence were ascribed to a two-photon process,and that of the blue upconversion luminescence was a three-photon process.     

氮偏压对α-GaAs_（1-x）N_x薄膜性能的影响

采用磁控溅射方法在硅片上制备了不同氮偏压下的非晶GaAs1-xNx薄膜,结合拉曼光谱仪和椭偏仪等手段对样品进行了表征。结果表明,掺入氮气后,α-GaAs薄膜的拉曼光谱有明显变化;随着氮偏压的升高,α-GaAs1-xNx薄膜的折射率和消光系数逐渐减小,其峰值向短波长略微移动。另外,α-GaAs1-xNx薄膜在红外和近红外波段内几乎是透明的。     

维生素E乙酸酯制备方法与光谱表征

利用新型催化剂固体超强酸SO42-/TiO2合成VE乙酸酯,研究催化剂用量、反应物配比、反应时间、反应温度等因素对合成的影响,通过模糊数学模型确定了最佳合成条件。最优合成工艺:温度40℃,时间3h,乙酸酐与VE摩尔比1.2,固体超强酸SO42-/TiO2催化剂用量1.0g,反应酯化率为96.6%。利用IR、元素分析和1H NMR对产物结构进行表征,证明得到的产物为VE乙酸酯。     

玻璃基底和表面粗糙度在氮化硅薄膜椭偏测量中的影响

在光谱椭偏测量中,玻璃基底的背反射会给测量结果造成较大影响。针对平板显示器件玻璃基底表面氮化硅镀膜进行了椭偏测量和模型计算。采用相干背反射模型“空气基底空气”计算并拟合得到与厂商数据符合较好的玻璃基底折射率。对氮化硅薄膜采用Tauc Lorentz色散模型进行了分析拟合,讨论了薄膜与基底界面层、表面粗糙度对光学常数及模型拟合的影响,表明在薄膜与基底间晶格失配的情况下,界面层的引入对改善拟合度是必要的。给出了薄膜体系的光学常数、薄膜结构的分析结果。     

东乌煤及不同化学组分的傅里叶红外分析

通过对东乌煤及其腐殖酸、抽提腐殖酸残煤、抽提沥青质残煤进行傅里叶红外分析,揭示抽提腐殖酸和抽提沥青质实验对煤结构的影响。结果表明:由于酸碱溶液的影响,腐殖酸残煤中芳香烃振动的峰,脂肪烃的伸缩振动峰,3400cm-1附近的峰都变弱;由于吡啶溶剂的影响,沥青质残煤中反映芳香结构的峰变尖锐;煤样的fa随H/C增加有减小趋势,而随着O/C的增加呈增大趋势;煤样中腐殖酸的脂肪链最长,支链最少;腐殖酸残煤的脂肪链最短,支链最多。