Broadband 1.53 μm emission in Er-doped Ga-Bi-Pb-Ge heavy metal oxide glasses

We investigated the thermal stability and spectroscopic properties of the 1.53 μm emission from ⁴I_13/2 → ⁴I_15/2 transition of Er³⁺ ions in Er³⁺/Yb³⁺-codoped Ga-Bi-Pb-Ge heavy metal oxide glass for use in broadband fiber amplifiers. It was noted that the addition of GeO₂ effectively enhanced the thermal stability of the heavy metal oxide glass studied. The emission peak located at approximately 1530 nm with a full width at half-maximum of approximately 58 nm. The measured lifetime and the calculated emission cross-section of this transition were 3.2 ms and 10.3×10⁻²¹ cm², respectively. As a result, Ga-Bi-Pb-Ge heavy metal oxide glasses were assumed to be potential host material for the 1.53 μm broadband optical fiber amplifiers.     

Growth mechanisms and their effects on the opto-electrical properties of CdS thin films prepared by chemical bath deposition

Chemically deposited CdS exhibits high sensitivity in the opto-electrical performance to the growth mechanisms. Hence it is of a great interest to study the effects of growth mechanisms on the opto-electrical performance in such films. Studies were carried out by the means of spectroscopic ellipsometry, and coupled with structural, optical, and electrical characterization. A range of bath temperatures (55 °C–95  °C) were used as the means to alter the growth mechanisms. Ion-by-ion process dominated deposition at lower bath temperatures throughout the length of the deposition. This mechanism produced films composed of single phase cubic crystals with corresponding opto-electrical properties inherent to such structures. Complex formations at higher bath temperatures supplement the sole ion-by-ion mechanisms with the cluster-by-cluster mechanism. This results in a mixed cubic/hexagonal structure, and deviation from stoichiometry. As a result, carrier concentrations and mobility increased nearly eight and four fold respectively. Resistivity decreased more than four times from 33.2 to 7.5 Ω cm. A noticeable decrease of, ~0.2 was observed in the refractive index and an increase of ~0.07 eV in the band gap is also reported. Nuclear magnetic resonance analysis confirms deviation from stoichiometry in the cluster-by-cluster mechanisms, resulting in interstitially trapped Cd⁺² and S⁻² ions. The trapped ions act as donors in the film enhancing its electrical performance.     

用磷钼酸喹啉重量法测定化学镀Ni-P镀层中的磷含量

介绍了磷钼酸喹啉重量法在化学镀镍磷镀层磷含量测定中的应用,并与GB/T 13913-92分光光度法和X射线能谱(EDS)法进行了比较.结果表明,本方法测定相对误差为-1.65%～4.21%,能准确测定镍磷镀层磷含量;与EDS法对Ni-P镀层的对比测定表明,EDS法所测结果比重量法普遍偏高.     

吐温20对锌电极性能影响的掠射椭偏法研究

利用掠射式椭圆偏振光谱法现场考察了添加吐温20前后碱性介质中锌电极析氢性能的变化及其对锌电极性能的影响.试验结果表明:吐温20作为电解液添加剂能够影响1mol/dm3KOH溶液中锌电极上的析氢过程,随着吐温20添加浓度的增加,对析氢的抑制作用增加.掠射椭圆偏振参量与电极电位关系进一步表明吐温20对锌电极析氢过程的抑制作用属于几何覆盖效应,同时也表明碱性电解液中添加适宜浓度的吐温20可以有效地抑制阴极过程中锌电极的析氢反应、枝晶形成与电极变形.     

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。     

催化臭氧氧化处理渗滤液RO浓液的氧化特性及光谱分析

腐殖质的去除效率是催化臭氧氧化降解垃圾渗滤液RO浓液中有机物的关键,活性炭负载金属铈催化剂（Ce-AC）催化臭氧氧化可有效提高腐殖质的去除效率。本文通过XRD、SEM和EDS等手段对Ce-AC催化剂进行表征,对比不同催化剂催化臭氧氧化对RO浓液COD去除及可生化性的影响,通过降解产物光谱分析明晰腐殖质的降解机制。结果表明,铈氧化物是以CeO₂萤石晶型的形式负载在AC上,负载后的AC比表面积和孔容积减少,平均孔径增加。催化剂Ce-AC对COD和UV₂₅₄的去除效果最好,为44.7%和67.3%,出水可生化性显著提升,B/C比从0.06提升到0.47。紫外-可见光谱表明,体系代表腐殖质的芳香类化合物降解效率明显;三维荧光光谱表明体系中腐殖质类物质被极大程度地降解,荧光区域积分的结果表明腐殖质类物质的去除效率达到了66.7%;傅里叶红外光谱表明腐殖质类物质被氧化分解成了相对小分子的碳水化合物和有机胺、硫和醇等。     

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.     

Morphology and molecular orientation in sexithiophene and N,N′-bis (n-octyl)-dicyanoperylenediimide heterostructures

We report on the growth mode of N,N′-bis (n-octyl)-dicyanoperylenediimide (PDI-8CN₂) on sexithiophene (T6) thin films, studied with different structural, morphological and optical techniques. We aim to individuate the most favorable conditions for the realization of heterostructure devices. The crystalline quality was established by X-ray patterns and Atomic Force Microscopy (AFM) images, and found to be generally high. The anisotropic optical constants extracted from ellipsometry measurements shed light on the mean molecular orientation in the PDI-8CN₂ film. AFM images evidence two different growth modes: at T6 thickness less than 2 monolayers (ML), the growth of PDI-8CN₂ on T6 is favored with respect to SiO₂, while, at higher thickness (2-6 ML), the situation is reversed. An optimum T6 underlayer thickness of approximately 1 ML provides the best quality of PDI-8CN₂ layer corresponding to the highest island dimension, the highest molecular order parameter, and the lowest roughness. Spectrum broadening was observed for extinction coefficient of PDI-8CN₂ in the heterostructures, as compared with a sole material film, and explained by two effects: increase in molecular disorder and formation of charge transfer complexes.