共查询到20条相似文献,搜索用时 281 毫秒
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用溶胶-凝胶法制得了In2O3纳米颗粒与Eu3 共掺的SiO2薄膜.使用X-射线衍射证实体系中形成了In2O3纳米颗粒,其数密度可以通过改变铟的掺杂浓度来进行良好的控制.在薄膜的光致发光光谱中观察到Eu3 离子的5Do-7FJ(J:O-4)特征发射峰,In2O3纳米颗粒的掺入使Eu3 的光致发光得到显著增强.通过光致发光激发光谱的测量进一步研究了In2O3纳米颗粒对Eu3 的光致发光增强的机制. 相似文献
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研究了用MOCVD法在蓝宝石(Al2O3)(0001)和(1120)衬底上制备ZnO薄膜时的生长特性.详细研究了采用Al2O3(0001)衬底时生长温度与压力的影响.由于存在比较大的晶格失配,一般容易得到ZnO纳米结晶,不容易获得既平坦且质量又好的ZnO薄膜.生长温度对薄膜-衬底界面的生长模式有很大的影响;而生长压力对ZnO纳米结晶的形状有决定性作用.通过适当控制生长温度及压力,可以得到ZnO薄膜或不同形状的纳米结构.当采用Al2O3(1120)衬底时,由于晶格失配较小,能保持平坦层状生长,临界膜厚远远大于采用Al2O3(0001)衬底的结果.在Al2O3(1120)衬底上制作了ZnO/MgZnO量子阱并研究了其光学特性.观察到了量子化能级间以及在载流子间的跃迁引起的发光.由压电效应引起的内建电场约为3×105V/cm.同时发现采用低温低压生长可以增大ZnO中受主杂质浓度,有利于获得p型ZnO. 相似文献
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近年来,Cu2O形貌控制合成的研究受到了广泛关注。首先,介绍了Cu2O一维、二维、三维结构中不同形貌的最新研究成果,分析了不同形貌的合成机理,并对各形貌的进一步研究趋势进行了探讨。然后,着重评述了Cu2O纳米笼、纳米骨架结构的研究进展,指出此类形貌的合成中主要涉及到氧化刻蚀作用和奥斯特瓦尔德熟化机理。最后,总结了Cu2O不同形貌研究的现状,指出了今后研究的方向,并提出了未来关于Cu2O形貌研究中主要的两大类趋势,即具有更多晶面的非传统型多面体结构以及具有更大比表面积、更高开放程度的纳米笼和纳米骨架结构。 相似文献
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离子诱导成核是大气气溶胶形成的重要路径之一。大气中团簇离子的形成,主要由宇宙射线电离空气产生的初级离子与H2O、H2SO4、HNO3、NH3、有机物等物质发生的离子-分子反应而产生。成核是团簇离子生长和蒸发相互竞争的一个过程,团簇离子生长到临界核尺寸时,便可自发生长。研究表明临界核大小约1.6 nm,对应的粒子的质量数在5000 amu以上。离子诱导生成的气溶胶粒子对气候的影响以及离子诱导成核在大气成核事件中是否占主要作用还存在很大争议,这需要进行进一步的外场观察、理论模拟、实验室研究来充分弄清离子诱导成核机理。 相似文献
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L. Lamagna M. FusiS. Spiga M. Fanciulli G. BrammertzC. Merckling M. MeurisA. Molle 《Microelectronic Engineering》2011,88(4):431-434
In this work we investigate the effect of different III-V surface passivation strategies during atomic layer deposition of Al2O3. X-ray photoelectron spectroscopy indicates that bare As-decapped and sulfur passivated In0.53Ga0.47As present residual oxides on the surface just before the beginning of the Al2O3 deposition while the insertion of a Ge interface passivation layer results in an almost oxide free Ge/III-V interface. The study of the initial growth regimes, by means of in situ spectroscopic ellipsometry, shows that the growth of Al2O3 on Ge leads to an enhanced initial growth accompanied by the formation of Ge-O-Al species thus affecting the final electrical properties of the stack. Alternatively, deposition on decapped and S-passivated In0.53Ga0.47As results in a more controlled growth process. The sulfur passivation leads to a better electrical response of the capacitor that can be associated to a lower oxide/semiconductor interface trap density. 相似文献
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Hanxing Liu Xiaoqin Sun Qinglin Zhao Jing Xiao Shixi Ouyang 《Solid-state electronics》2003,47(12):2295
In the present paper, the microstructures of SrTiO3 particles obtained in two different methods were examined by scanning electron microscopy (SEM) and X-ray diffraction pattern (XRD). The two synthesis techniques included a conventional mixed solid method and a molten salt synthesis method (MSS), which proceeded through two steps. In the first, precursor Sr3Ti2O7 particles were synthesized. Tabular SrTiO3 crystals were synthesized via the superposition of the SrTiO3 basic cell on the interface of Sr3Ti2O7 particles. The microstructures of SrTiO3 particles synthesis in those two ways were quite different. The microstructures of SrTiO3 obtained by MSS method were high purity and obviously tabular in structure. Oriented growth faces included typical (0 0 1), (1 0 0), (1 1 0), etc. The mechanism of the oriented growth of tabular SrTiO3 could be considered as the superposition of coordination polyhedron Ti–O6 octahedron basic cell on the interface of Sr3Ti2O7 particles. 相似文献
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用第一性原理计算了Sn 替位Ga1.375In0.625O3化合物的Ga 原子(Ga1.25In0.625Sn0.125O3)和Sn 替位Ga1.375In0.625O3化合物的In原子(Ga1.375In0.5Sn0.125O3)的结构、电子能带和态密度。Ga1.25In0.625Sn0.125O3半导体材料比Ga1.375In0.5Sn0.125O3材料具有大的晶格参数和强的Sn–O离子键。在Sn掺杂 Ga1.375In0.625O3化合物中,Sn 原子优先取代In 原子。Sn掺杂 Ga1.375In0.625O3化合物显示n型导电性, 杂质能带主要由Sn 5s 态组成。Ga1.375In0.5Sn0.125O3化合物的光学带隙大于Ga1.25In0.625Sn0.125O3化合物的光学带隙。 Ga1.25In0.625Sn0.125O3 具有小的电子有效质量和大的电子迁移率,Ga1.375In0.5Sn0.125O3 具有多的相对电子数和好的导电性。 相似文献
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This paper describes the mechanism of selective Si3N4 etching over SiO2 in capacitively-coupled plasmas of hydrogen-containing fluorocarbon gas, including CHF3, CH2F2 and CH3F. The etch rate of Si3N4 and SiO2 is investigated as a function of O2 percentage in all plasma gases. Addition of O2 in feed gases causes plasma gas phase change especially H density. The SiO2 etch rate decreases with increase of O2 percentage due to the decline of CFx etchant. The Si3N4 etch rate is found to be strong correlated to the H density in plasma gas phase. H can react with CN by forming HCN to reduce polymer thickness on Si3N4 surface and promote the removal of N atoms from the substrate. Thus the Si3N4 etch rate increases with H intensity. As a result, a relative high selectivity of Si3N4 over SiO2 can be achieved with addition of suitable amount of O2 which corresponds to the maximum of H density. 相似文献
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分别采用旋涂法和水热法在FTO衬底上制备Co3O4种子层和Co3O4薄膜,再在Co3O4薄膜上水热生长Fe2O3纳米棒,获得了高质量的Co3O4/Fe2O3异质结复合材料。通过改变Fe2O3前驱体溶液浓度来改变异质结复合材料中Fe2O3组分的含量。结果表明,Fe2O3纳米棒覆盖在呈网状结构的Co3O4薄膜上,随着Fe2O3前驱体溶液浓度即Fe2O3组分含量的增加,Co3O4/Fe2O3异质结复合材料对紫外光的响应逐渐增强,当Fe2O3前驱体溶液浓度为0.015mol/L时,异质结复合材料有着很好的光电稳定性,并表现出较高的响应率(12.5mA/W)和探测率(4.4×1010Jones)。 相似文献
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Effects of excess Bi concentration, buffered Bi2O3 layer, and Ta doping on the orientation and ferroelectricity of chemical-solution-deposited (CSD) Bi3.25La0.75Ti3O12 (BLT) films on Pt/SiO2/Si(100) were studied. The optimum concentration of excess Bi added to the BLT films to achieve a larger remanent polarization
(2Pr) was 10 mol.%. The buffered Bi2O3 layers could reduce the temperature for c-axis-oriented growth of BLT films from 850°C to 700°C. However, two-step annealing,
i.e., first annealed at 650°C and then annealed at a temperature of 700–850°C, could effectively suppress the c-axis-oriented
growth and thus improve the 2Pr of BLT films. The improvement of the 2Pr of BLT films can be explained in terms of the large
polarization along the a-axis orientation and buffered Bi2O3 layers, which compensate the BLT films for Bi evaporation during annealing. The Ta doping can induce two contrary effects
on the 2Pr of BLT films. For the (Bi3.25La0.75)(Ti3−xTax)O12 (BLTTx) films with x=0.005, the effect of a decrease of oxygen vacancies would be dominant, resulting in the improvement
of 2Pr. Because the Ta concentration (x) in the BLTTx films exceeds 0.01, the effect of a decrease of grain size would become
dominant, resulting in the degradation of 2Pr. 相似文献
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The interfacial reactions between liquid In-49Sn solder and Ni substrates at temperatures ranging from 150°C to 450°C for
15 min to 240 min have been investigated. The intermetallic compounds formed at the In-49Sn/Ni interfaces are identified to
be a ternary Ni33In20Sn47 phase using electron-probe microanalysis (EPMA) and x-ray diffraction (XRD) analyses. These interfacial intermetallics grow
with increasing reaction time by a diffusion-controlled mechanism. The activation energy calculated from the Arrhenius plot
of reaction constants is 56.57 kJ/mol. 相似文献
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The effect of various electrodes (Al, W, TiN) deposited by evaporation (Al) and sputtering (W, TiN) on the electrical characteristics of thermal thin film (15-35 nm) Ta2O5 capacitors has been investigated. The absolute level of leakage currents, breakdown fields, mechanism of conductivity, dielectric constant values are discussed in the terms of possible reactions between Ta2O5 and electrode material as well as electrode deposition process-induced defects acting as electrically active centers. The dielectric constant values are in the range 12-26 in dependence on both Ta2O5 thickness and gate material. The results show that during deposition of TiN and Al a reaction that worsens the properties of Ta2O5 occurs while there is not an indication for detectable reduction of Ta2O5 when top electrode is W, and the leakage current is 5-7 orders of magnitude lower as compared to Al and TiN-electroded capacitors. The high level of leakage current for TiN and Al gate capacitors are related to the radiation defects generated in Ta2O5 during sputtering of TiN, and damaged interface at the electrode due to a reaction between Al and Ta2O5, respectively. It is demonstrated that the quality of the top electrode affects the electrical characteristics of the capacitors and the sputtered W is found to be the best. The sputtered W gate provides Ta2O5 capacitors with a good quality: the current density <7 × 10−10 A/cm2 at 1 V (0.7 MV/cm, 15 nm thick Ta2O5). W deposition is not accompanied by an introduction of a detectable damage leading to a change of the properties of the initial as-grown Ta2O5 as in the case of TiN electrode. Damage introduced during TiN sputtering is responsible for current deterioration (high leakage current) and poor breakdown characteristics. It is concluded that the sputtered W top electrode is a good candidate as a top electrode of storage capacitors in dynamic random access memories giving a stable contact with Ta2O5, but sputtering technique is less suitable (favorable) for deposition of TiN as a metal electrode due to the introduction of radiation defects causing both deterioration of leakage current and poor breakdown characteristics. 相似文献
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High-quality ZnO(Ga2O3) thin films have been co-evaporated by reactive electron-beam evaporation in an oxygen environment. The effect of Ga2O3 on the structural and optical properties has been investigated. X-ray diffraction (XRD) measurements have shown that the ZnO(Ga2O3) alloys are c-axis-oriented. The alloy containing 28% of Ga2O3 showed the best crystallinity. Photoluminescence on ZnO(28%Ga2O3) reveals an enhancement of the ultraviolet near band edge emission at 380 nm while the intensity of the deep-level emissions weakens. A reduction of the oxygen vacancies as well as the reduction of the zinc interstitials with gallium may explain this effect. Thus, the possibility of transitions of electron in the conduction band to a deep acceptor level due to zinc interstitials may decrease. Finally, ellipsometric measurements show that the optimum weight concentration of gallium oxide in the alloys is 28%, thus correlating with the XRD and photoluminescence measurements. 相似文献