Chalcogenide Glass Thin Films and Planar Waveguides

Over the past decade, we have carried out a comprehensive development program to produce high-purity Ga:La:S and Ge:S glasses and further process these glasses into thin films. In this paper, we discuss the general properties of these glass systems and the techniques used to obtain thin films. We demonstrate the ability to deposit high-quality films ranging in thickness from nanometers to several millimeters by several methods, including chemical vapor deposition technique, a technique not usually applied to chalcogenide glasses.     

Thin Copper, Gold, and Aluminum Films on Silicate Glass

The composition and structure of thin copper, gold, and aluminum films deposited on a substrate made of vitreous quartz are investigated. The composition of the film – substrate interfaces is analyzed.     

浮法玻璃熔窑内玻璃液温度的测量

玻璃熔窑内的温度对产品质量起决定性的作用,合适的温度制度有利于玻璃质量的提高,能最大限度地节约燃料并延长熔窑寿命.熔窑空间温度容易测量和控制,熔窑内玻璃液的温度却很难实现实时检测,对于玻璃生产,玻璃液温度比熔窑空间温度更为重要.通过对熔窑内玻璃液温度的测量,探索熔窑内玻璃液在不同区域的温度特性.     

Coalescence of Thin Films of Gold Condensed on Glass

Thin films of gold were deposited by evaporation onto glass surfaces generated by slow fracture in a vacuum. Such films characteristically show an agglomerated or coalesced structure. Deliberate contamination of the substrate and growing films with O₂, CO₂, H₂O, and Ar by exposure to a pressure of 0.0013 Pa (1×10⁻⁵ torr) of the gas had no effect on the structure of films of an average thickness of 5 nm (50 Å). Similar treatment of the films with N₂ resulted in a decrease in the extent of agglomeration of the gold. Treatment of the substrate with N₂ prior to the deposition caused an even greater decrease in agglomeration. Films of an average thickness of 2 nm (20 Å) were not affected detectably by the N₂ treatment. The available evidence indicated that the N₂ acted directly on the glass and that the structure of the films was unaffected by minor variations in the age of the surface or by differences in the speed of the fracture which generated the surface. The film structure was not changed by extended exposure to the atmosphere.     

钠钙玻璃熔体电阻率测量影响因素及边界条件研究

玻璃熔体电阻率是设计玻璃电熔窑或电助熔窑的关键参数之一,研究玻璃熔体电阻率测量的边界条件对获得精确电阻率值极其重要。本文基于欧姆定律,构建玻璃熔体电阻率测量装置,探讨了馈入电压、交流电频率、试样颗粒尺寸和填充率等因素对钠钙玻璃熔体在900~1 450 ℃电阻特性的影响。结果显示,当馈入电压为2~10 V,交流电频率为1 kHz,试样颗粒尺寸为830~1 700 μm,填充率为80%,降温速率为2 ℃/min时,电阻率测量结果的误差在各温度段都小于1。该研究可以为玻璃熔体电阻率测量提供参考,进而支撑玻璃电熔窑及电助熔窑电加热系统的设计,实现难熔及易挥发玻璃的熔化。     

非晶态聚合物玻璃化转变温度的测定方法综述

非晶态或非完全结晶的聚合物的玻璃化转变温度(T_g)是高分子材料的重要物理参数,直接影响材料的使用和加工性能,准确测定聚合物的T_g具有重要意义。本文介绍了常用的几种测量聚合物T_g的方法,包括差示扫描量热法、热机械分析法、动态热机械分析法、核磁共振法和电子自旋共振法。对比了它们的优缺点及适用条件,以期为科研工作者和实验人员根据样品状态和研究目的选择适宜的测定方法提供参考。     

Electrode Properties of Halogenide-Chalcogenide Glasses and Amorphous Thin Films Fabricated by Chemical Deposition

Multicomponent thin halogenide-chalcogenide CuI–PbI₂–As₂Se₃, CuI–AgI–As₂Se₃, and PbI₂–AgI–As₂Se₃ films are synthesized by the chemical deposition method from halogenide-chalcogenide glass solutions in n-butylamine and the electrode properties of the glass and films are examined. It is established that the electrode properties of halogenide-chalcogenide glass and films with similar compositions are virtually the same. The similarity of the electrode parameters of halogenide-chalcogenide glass and films can be explained by the preservation of the glass polymer structure upon dissolution in n-butylamine and film deposition from the solution.     

Metastable Tantalum Oxide Formation During the Devitrification of Amorphous Tantalum Thin Films

Microstructural evolution during the devitrification of amorphous tantalum thin films synthesized via pulsed laser deposition was investigated using in situ transmission electron microscopy (TEM) combined with ex situ isothermal annealing, bright‐field imaging, and electron‐diffraction analysis. The phases formed during crystallization and their stability were characterized as a function of the chamber pressure during deposition, devitrification temperature, and annealing time. A range of metastable nanocrystalline tantalum oxides were identified following devitrification including multiple orthorhombic oxide phases, which often were present with, or evolved to, the tetragonal TaO₂ phase. While the appearance of these phases indicated the films were evolving to the stable form of tantalum oxide—monoclinic tantalum pentoxide—it was likely not achieved for the conditions considered due to an insufficient amount of oxygen present in the films following deposition. Nevertheless, the collective in situ and ex situ TEM analysis applied to thin film samples enabled the isolation of a number of metastable tantalum oxides. New insights were gained into the transformation sequence and stability of these nanocrystalline phases, which presents opportunities for the development of advanced tantalum oxide‐based dielectric materials for novel memristor designs.     

自洁净玻璃纳米TiO2薄膜制备的研究进展

自洁净玻璃是采用特有的镀膜工艺在玻璃表面上制备纳米TiO2薄膜的新型环保智能产品,具有广泛的用途,其中纳米TiO2薄膜的制备是关键。综述了自洁净玻璃表面纳米TiO2薄膜的制备方法,包括基片的清洗方法、溶胶的制备方法及薄膜的涂覆方法。     

Enthalpy and Anisotropy Relaxation of Glass Fibers

Optical birefringence and calorimetric studies have been conducted with respect to structural relaxation of E-glass (a type of calcium–alumosilicate glass system) fibers. Upon fiber drawing, the liquid of E-glass is thermally hyperquenched and mechanically stretched. Hyperquenching (cooling rate >10⁶ K/min) leads to higher enthalpy state of liquids, and thereby, to a higher fictive temperature than normal quenching (20 K/min), whereas stretching results in structural anisotropy of glasses, i.e., a certain degree of preferred structural orientation (stretched network) along the axial direction of the fibers, which is quantified by the optical birefringence. Simultaneous relaxation of both anisotropy and excess enthalpy (relative to the enthalpy of a glass cooled at the standard rate of 20 K/min) upon static annealing and dynamic heating is observed, both of which can be described using the Kohlrausch function. However, there is a striking difference between the birefringence and the excess enthalpy relaxations. The birefringence decays much faster than does the excess enthalpy during annealing. These observations imply that the birefringence decay results from fast relaxation of the local structure, while the enthalpy relaxation results from slow relaxation of larger domains of the network.     

Annealing Temperature Effect on Bismuth Induced Crystallization of Hydrogenated Amorphous Silicon Thin Films

Silicon - In this work, we emphasis on the Bismuth induced crystallization of hydrogenated amorphous silicon (a-Si) thin films. 50 nm of bismuth thin films are deposited by vapor...     

纳米WO3薄膜的制备方法及其性质研究

纳米WO3薄膜是一种典型的功能性纳米材料,在电致变色、气敏性、共催化及光致变色等方面都有着广阔的应用前景。综述了纳米WO3薄膜的几种常用制备方法并进行了比较,对纳米WO3薄膜的发展前景作出展望。     

纳米WO3薄膜的制备方法及其性质研究

纳米WO3薄膜是一种典型的功能性纳米材料,在电致变色、气敏性、共催化及光致变色等方面有着广阔的应用前景。本文综述了纳米WO3薄膜的几种常用制备方法并进行了比较,最后对纳米WO3薄膜的发展前景作出展望。     

Fabrication and Ultraviolet Absorption of Sol–Gel-Derived Germanium Oxide Glass Thin Films

Germanium oxide glass thin films were prepared by the sol–gel method and annealed under reduced atmosphere to create more oxygen-deficient defects. The densification and crystallization were examined depending on sintering and annealing conditions. Thus, homogeneous germanium oxide thin films with a high content of oxygen vacancies were fabricated. Ultraviolet absorption and oxygen vacancies of the films were investigated as a function of annealing temperature and time. Optical absorption in the 5-eV region due to the formation of oxygen vacancies is enhanced with increasing annealing temperature and time. The formation energy of oxygen vacancies is calculated to be about 1.0 eV.     

Direct Synthesis and Characterization of High Titanium-Loading Hexagonal Mesostructured Silica Thin Films

High titanium-loading hexagonal mesostructured silica thin films (Ti-HMSTF) have been successfully synthesized by carefully controlling two factors. One is the hydrolysis and condensation reaction of titanium alkoxide and the other is the aging condition of as-made Ti/Si mixed thin films. The former was controlled by adding acetylacetone (AcAc) as a Ti chelating agent. Regarding the latter, aging under a hydrothermal water vapor ambient environment was found to be effective in synthesizing Ti-HMSTFs with well-defined mesostructures. The maximum molar ratio of Ti/Si in the Ti-HMSTF materials attained a value of 0.3 (referred to as Ti-HMSTF-0.3) for the as-made films. These materials were subjected to a specific hydrothermal aging process, which was prepared from a precursor solution containing AcAc with the molar ratio AcAc/Ti=1. Small angle X-ray diffractometry (SA-XRD) and transmission electron microscopy (TEM) demonstrated that Ti-HMSTF-0.3 had a highly ordered 2-dimensional hexagonal mesostructure. This 2D hexagonal mesostructure was thermally stable even after the removal of the triblock copolymer template by calcination at 450°C for 4 h. Moreover, small amounts of TiO₂ anatase nanocrystals with a size of about 3 nm were formed in the calcined Ti-HMSTF-0.3. O(1s) X-ray photoelectron spectroscopy (XPS) analysis indicated that the incorporation of titanium into the HMSTF was through the Si–O–Ti bonds. The Ti(2p) XPS showed that the binding energy of the titanium in HMSTF decreased with increasing Ti loading.     

The Crystallization of Amorphous Aluminum Oxide Thin Films Grown on NiAl(100)

The crystallization of amorphous aluminum oxide thin films formed on NiAl(100) has been investigated using in‐situ low energy electron microscopy, low energy electron diffraction, and scanning tunneling microscopy. It is found that both the annealing temperature and annealing time play crucial roles in the crystallization process. A critical temperature range of 450°C–500°C exists for the crystallization to occur within a reasonably short annealing time. The initially uniform oxide film first becomes roughened, followed by coalescing into amorphous‐like oxide islands; further annealing results in the conversion of the amorphous oxide islands into crystalline oxide stripes. The density of the crystalline oxide stripes increases concomitantly with the decrease in the density of the amorphous oxide islands for annealing at a higher temperature or longer time.     

Two-Layer Crystallization of Amorphous YMnO3 Thin Films on Si (100) Substrates

During a rapid thermal annealing process at 850°C in a N₂ ambient, an as-deposited amorphous YMnO₃ thin film on Si (100) substrates was crystallized with two distinct layers. High-resolution transmission electron microscopy showed a top layer of c -axis-oriented YMnO₃ and a bottom layer of polycrystalline YMnO₃ in the 100-nm-thick YMnO₃ thin film. The abrupt change of the crystalline orientation from the c -axis-preferred orientation to the random orientation is caused primarily by high stress induced by the c -axis-oriented YMnO₃ layer. High-resolution X-ray diffraction showed that the c -axis-oriented YMnO₃/polycrystalline YMnO₃ structure effectively relieved the stress.