Effect of Wafer Temperature on High Aspect Ratio Hardmask Etching

Fluorocarbon-based chemistries were used to study the effect of wafer temperature on the etch of high aspect ratio hardmasks composed of SiO₂ and SiN_x layers. It is found that etch stop can occur easily at high temperature. The rate of polymer deposition plays an important role in etch stop. The etching rates were found to be inversely proportional to the wafer temperature. Such a relation indicates a negative activation energy in the rate expression of hardmask etching using fluorocarbon plasma. It also implies that in hardmask etching, complicated gas-surface, but not simple one-step, reactions are involved. Different wafer surface temperature can provide different degree of activation for etching reactions. Analysis of etching rate and optical emission trends indicates that CF_x may contribute more than F does in the etch of SiO₂ and SiN_x, since polymer-rich etching chemistries were used. Based on the temperature-dependent etching rate, we propose a reaction mechanism for the reaction trends observed in hardmask etching.     

大长径比有序多孔阳极氧化铝模板的制备及用于镍纳米线阵列

报道一种恒电流二次氧化制备大长径比(>1000)阳极氧化铝(AAO)模板的方法,研究氧化时间和氧化电流密度分别对制备的AAO模板的表面形貌、孔径大小、厚度等的影响.结果表明,AAO模板的表面形貌及厚度n受m氧、厚化度电约流为密2度00及μ氧m、化长时径间比的为影10响0;-当13氧00化的电高流质密量度A为AO8模m板A·.c采m用-2电时化,氧学化沉1积8方h能法在制制备备出的孔A径A为O模15板0-的20孔0中成功制备了Ni纳米线阵列,分别用扫描电镜(SEM)、高分辨透射电镜(HRTEM)、X射线衍射(XRD)和X射线能量散射光谱(EDS)对其进行了表征;结果显示,制备的Ni纳米线排列整齐有序,每根Ni纳米线直径几乎相同,约150nm,长度约为180-200μm,长径比为1200-1300,与AAO模板的参数一致.研究了Ni纳米线阵列的长径比对其磁性能的影响,发现大长径比的Ni纳米线阵列具有明显的磁各向异性,而长径比约为200的Ni纳米线阵列未表现出明显的磁各向异性.本文结果表明,恒电流二次氧化方法能制备大长径比的AAO模板,并能用于制备大长径比的一维纳米材料阵列,可望在制备具有特殊光学、磁学等性能材料方面得到应用.     

Effect of Electrical Contact on the Performance of Bi2S3 Single Nanowire Photodetectors

Bi₂S₃ single‐crystalline nanowires are synthesized through a hydrothermal method and then fabricated into single nanowire photodetectors. Due to the different contact barrier between the gold electrode and Bi₂S₃ nanowires, two kinds of devices with different electrical contacts are obtained and their photoresponsive properties are investigated. The non‐ohmic contact devices show larger photocurrent gains and shorter response times than those of ohmic contact devices. Furthermore, the influence of a focused laser on the barrier height between gold and Bi₂S₃ is explored in both kinds of devices and shows that laser illumination on the Au?Bi₂S₃ interface can greatly affect the barrier height in non‐ohmic contact devices, while keeping it intact in ohmic contact devices. A model based on the surface photovoltage effect is used to explain this phenomenon.     

聚吡咯纳米线(管)的合成

聚吡咯纳米线(管)是一种极具应用潜力的新材料.本文综述了聚吡咯纳米线(管)的各种合成方法.并对各方法的优缺点进行了评述.     

单体烃氢同位素测试系统高温热转化装置的研制

研制了单体烃氢同位素在线测试系统(GC-TC-IRMS)中的高温热转化装置(TC).该装置主要由高温电热元件、高温裂解管、温控系统等部分组成.实验表明,高温热转化装置控温精度良好(±3 ℃);在1250～1500 ℃之间选择13个温度点,并选用最稳定的烃类化合物CH4,在每个温度点进行反复实验对比(n≥6),甲烷氢同位素值(δDCH4)随反应温度增高逐渐变轻;通过对标准多元气态烃类化合物、标准液态烃类化合物及原油样品测试结果的对比分析,表明所研制的TC具有很好的稳定性与可靠性,δDn-alkane的测试精度优于±2.5‰, 完全达到研究需求.     

敏化染料分子长径比对太阳能电池性能的影响

采用同一系列但分子长径比不同的3种染料:2-氰基-3-[2-[4-{2-[4-N,N-二(4-甲基苯基)氨基苯基]乙烯基}-苯基氨基)-嘧啶-5-取代基]-丙烯酸(MTPA-Pyc)、2-氰基-3-(4-{2-[4-N,N-二(4-甲基苯基)氨基苯基]乙烯基}-苯基)-丙烯酸(MTPAcc)和2-氰基-3-[4-N,N-二(4-甲基苯基)氨基苯基]-丙烯酸(MTPAc),研究了在不同吸附溶剂中3种染料分子在Ti O2上的吸附量和聚集态,探讨了敏化染料分子长径比对染料敏化太阳电池性能的影响.结果表明,MTPAcc具有最合适的分子长径比,其在Ti O2表面的吸附量及应用的光电性能最高;吸附溶剂的极性增大有利于提高染料的吸附量,但也会影响染料分子的聚集态.当以四氢呋喃为吸附溶剂时,MTPAcc在Ti O2表面的吸附量大且不发生聚集,对应的敏化太阳能电池器件在所有结果中表现最好,在490 nm处的单色光光电转化效率(IPCE)极值达到84%,总光电转化效率(η)达到5.72%.     

Effect of Electrolytes on Redox Reactivity of Polypyrrole

Doping and dedoping characteristics of polypyrrole (PPy) formed electrochemically have been examined by means of energy-dispersive X-ray spectroscopy (EDS). Dodecylsulfate ions (DS⁻) and perchlorate ions (ClO⁻₄) were embedded simultaneously in PPy when both ions were present on the polymerization of pyrrole. Sequential formation of PPy in the single dopant system allowed PPy/ClO₄ to grow in the bulk of PPy/DS but not vice versa. DS⁻ was embedded not to leave the polymer on reduction but ClO⁻₄ moved in and out of the polymer on redox reaction. Cyclic voltammetry was employed to determine the redox reactivity of PPy in different electrolyte systems. NaClO₄ was a better electrolyte for cyclic redox reaction than LiClO₄ or KClO₄. NaCl was a good electrolyte for cyclic redox reaction but Cl⁻ failed to penetrate in the PPy/DS bulk on reoxidation. The cyclic redox reactivity lasted longest when PPy/DS was redox-cycled sequentially in the NaCl electrolyte system and then in the NaClO₄ system. © 1997 John Wiley & Sons, Ltd.     

Effect of Electropolymerization Condition on Polypyrrole Schottky Barrier

Schottky barriers of some polypyrrole(PPy) nitrate film, which was prepared electro-chemically from ethyl alcohol solution, and poly(N-methylpyrrole) (PNMP) films were observed and investigated by means of measuring the current density (J)-voltage(V) characteristics of Al/PPy/ITO and Al/PNMP/ITO. A strong effect of the film thickness on the rectification ratios was recognized for the PPy films. The Schottky barrier parameters were evaluated from J-V plots.     

水滑石晶体长厚比及晶粒尺寸控制方法研究

层状双金属氢氧化物（LayeredDoubleHydrox－ides，简称LDH）是一类重要的无机晶体材料，因其具有层状结构以及层板元素的可调控性和层间阴离子的可交换性，在催化、离子交换、吸附、医药犤１～８犦等方面具有广泛的用途，已受到人们越来越广泛的关注。近年来，随该类材料应用领域的不断拓展，在许多情况下要求LDH晶体具有小的粒径尺寸，以便最大限度地发挥其功能性。例如将LDH作为阻燃剂犤９犦使用，小粒径粉体可增强与聚合物基材的相容性，提高材料的阻燃、抑烟和力学性能。另一方面，因LDH具有层状结构，在复合材料中其层板能有效…     

Effect of Gate Electric Field on Single Organic Molecular Devices (cited: 3)

Based on the first-principles computational method and elastic scattering Green's function theory, we have investigated the effect of gate electric field on electronic transport properties of a series of single organic molecular junctions theoretically. The numerical results show that the molecular junctions that have redox centers and relatively large dipole moments parallel gate direction can respond to the gate electric field remarkably. The current-voltage properties of 2,5-dimethyl-thiophene-dithiol present N-channel-metal-oxide-semiconductor-like characteristics. Its distinct current-voltage properties can be understood from the evo-lution of eigenvalues, coupling energies, and atomic charges with gate electric field.     

单缺位Dawson型磷钨杂多酸掺杂聚吡咯的过氧化氢传感器研究

在金电极上，用电化学方法将单缺位Ｄａｗｓｏｎ型磷钨杂多酸盐ａ２－Ｋ１０Ｐ２Ｗ１７Ｏ６１１５Ｈ２Ｏ的阴离子（Ｐ２Ｗ１７）掺杂到聚吡咯（ＰＰｙ）薄膜中，制成ＰＰｙ／Ｐ２Ｗ１７／Ａｕ的Ｈ２Ｏ２传感器。研究了它对 Ｈ２Ｏ２电还原过程的催化机理．其 ｉｐｅ与 ＣＨ２Ｏ２在 ６．０× １０－５～８． ８×１０－４ ｍｏｌ／Ｌ和８．８×１０－４～６．０×１０－３ｍｏｌ／Ｌ范围内呈良好的线性关系，检测下限为４．０×１０－５ｍｏｌ／Ｌ。用于模拟水样中Ｈ２Ｏ２的测定，结果较满意．     

掺杂离子对聚吡咯膜的电化学容量性能的影响

用电化学方法制备了分别以对甲基苯磺酸根(TOS-), 高氯酸根(ClO-4)和氯离子(Cl-)掺杂的聚吡咯(PPy)膜. 用循环伏安(CV)、恒电流充放电和电化学阻抗谱(EIS)等测试了它们的电化学容量性能. 用扫描电镜(SEM)和X射线衍射(XRD)分别研究了这三种PPy膜的形貌和结构. 研究发现, 由于具有疏松多孔的形貌和更有序的分子链结构, PPy-TOS和 PPy-Cl膜具有较好的充放电能力, 在深度充放电时仍具有很小的电化学电阻, 其离子扩散接近理想电容器的离子扩散机理. PPy-Cl(聚合电量2 mAh·cm-2)的比容量在扫描速率为5 mV·s-1时高达270 F·g-1, 扫描速率200 mV·s-1时仍高达175 F·g-1, 特别是, 其比能量高达35.3 mWh·g-1. PPy-TOS由于有质量较大的掺杂离子(TOS-)因而比容量略低(146 F·g-1, 扫描速率5 mV·s-1), 但具有超快速充放电能力, 在扫描速率为200 mV·s-1时, 比容量为123.6 F·g-1, 其比功率高达10 W·g-1. 并且, 两种电极材料均具有稳定的电化学循环性能.     

The Effect of Substrate on the Annealing of Poly(butylene succinate) Single Crystals

The morphological evolution of poly(butylene succinate) (PBS) solution‐grown single crystals during annealing was studied using hot‐stage atomic force microscopy. Their morphology changed with increasing temperature and annealing time. The annealing behavior and melting temperature were found to be affected by the substrate. Morphological changes occurred at a much lower temperature on an amorphous carbon film than that on a mica surface. Moreover, the pattern of morphological evolution of the single crystals on a carbon film was different from that on a mica surface. Since the PBS melt had a larger contact angle on the mica surface, these differences in the melting behavior were ascribed to the different interfacial interactions between the chain‐folded surface of the single crystal and the substrate.

     

Manipulation of Multicomponent Langmuir-Blodgett Films of Electrically Conductive Polymers: Polypyrrole and Poly(3-Hexylthiophene)

Abstract

Multicomponent Langmuir-Blodgett (LB) films containing poly-pyrrole, 3-octadecanoyl pyrrole, and poly(3-hexylthiophene) were fabricated via a novel in-situ polymerization process. In this process, pyrrole monomer is polymerized at the air-subphase interface in the presence of poly(3-hexylthiophene) by using a subphase containing 1 wt% FeCl₃. The resultant electrically conductive films could be readily deposited onto solid substrates as Z-type films by the vertical lifting method. By using visible absorption, x-ray diffraction, and FTIR measurements, it was found that all three components were present within the transferred films, with the polypyrrole chains assuming a preferential orientation parallel to the film surface. The conductivities of the mixed LB films were as high as 1.0 S/cm, and the stability of the conductivity was very good. Chemical doping of poly(3-hexylthiophene) within the film with strong oxidizing agents such as I₂ further enhanced the conductivity of the film.     

Fabricating and Tailoring Polyaniline (PANI) Nanofibers with High Aspect Ratio in a Low‐Acid Environment in a Magnetic Field

In a 0.010 m HCl solution, we successfully transformed irregular polyaniline (PANI) agglomerates into uniform PANI nanofibers with a diameter of 46–145 nm and a characteristic length on the order of several microns by the addition of superparamagnetic Fe₃O₄ microspheres in a magnetic field. The PANI morphological evolution showed that the PANI nanofibers stemmed from the PANI coating shell synthesized on the surface of the Fe₃O₄ microsphere chains. It was found that the magnetic field could optimize the PANI nanofibers with a narrow diameter size distribution, and effectively suppressed secondary growth. When compared with other microspheres (like silica and polystyrene), only the use of superparamagnetic Fe₃O₄ microspheres resulted in the appearance of PANI nanofibers. Attempts to form these high‐quality PANI nanofibers in other concentrations of HCl solution were unsuccessful. This deficiency was largely attributed to the inappropriate quantity of aniline cations.     

Effect of the Dopant Nature on the Response of Sensor Arrays Based on Polypyrrole

The effect of the nature of the dopant on the response of a sensor array based on films of polypyrrole under the influence of the vapor of various organic solvents was studied. It was found the electric conductivity of the polymer can both increase and decrease during the action of analytes on electropolymerized films of polypyrrole. It is suggested that the main factors determining the response of polypyrrole are the morphology of the films and the type of charge carriers in the polymer, which depend on the nature of the dopant anion, and also the polarity and nucleophilicity/electrophilicity of the analyte. The responses of polypyrrole and polyaniline are compared, and the effect of the nature of the conducting polymer on them is analyzed. __________ Translated from Teoreticheskaya i Eksperimental'naya Khimiya, Vol. 41, No. 5, pp. 265–271, September–October, 2005.