纳米晶Ti薄膜的结构研究

用高密度、高电离度的电子迴旋共振等离子体溅射方法在室温基片上沉积出纳米晶Ti薄膜,基体为玻璃、NaCl单晶、纯Al等。对Ti薄膜的结构、形貌和成分进行X射线衍射(XRD),透射电子显微镜(TEM)和X射线光电子能谱(XPS)分析,表明所沉积的Ti薄膜是平均粒径d<10nm,晶粒大小均匀且具有比较稳定的fcc反常结构的纳米晶粒膜。我们还较系统地研究了各工作参数对Ti薄膜的晶体结构、晶粒尺寸、成膜速率以及对基体粘附力的影响,分析了成膜机理。 关键词：     

纳米引晶法选择性生长金刚石薄膜

通过传统的光刻工艺和纳米引晶技术,在抛光的单晶Si衬底上形成带有 超细金刚石纳米粉的引晶图案,并利用该图案与抛光Si处金刚石成核密度的巨大差异,实现 金刚石薄膜的高选择比生长。该方法具有工艺简单、沉积效率高、选择比高、对底无任何损 伤等优点。同时,这种方法很容易在不同衬底上实现金刚石薄膜的大面积选择性生长。     

金属与金刚石薄膜接触的电学特性研究

用热丝辅助化学汽相沉积技术在Si衬底上合成了含少量受主型杂质的近于本征的金刚石薄膜，并研究了三种金属（Cu，Ag和Al）与它接触的电学特性，以及退火对接触特性的影响．结果表明Cu，Ag与金刚石薄膜接触的电学特性比较类似，而Al则明显不同；而且退火对它们的接触特性影响很大 关键词：     

氢稀释对纳米晶硅薄膜晶化特性的影响及薄膜生长机理

以SiH₄与H₂作为前驱气体,采用射频等离子增强化学气相沉积技术制备了纳米晶硅薄膜.利用Raman散射和红外吸收光谱等技术,对不同氢稀释比条件下薄膜的微观结构和键合特性进行了研究.结果表明,随着氢稀释比增加,薄膜的晶化率明显提高,而氢稀释比过高时,薄膜晶化率呈现减少趋势.红外吸收光谱分析表明,纳米晶硅薄膜中氢的键合模式与薄膜的晶化特性密切相关.随着氢稀释比增加,薄膜中整体氢含量和SiH₂键合密度明显减少,而在高氢稀释比条件下,氢稀释比增加导致薄膜中SiH₂键合密度和整体氢含量增加.     

氢稀释对纳米晶硅薄膜晶化特性的影响及薄膜生长机理

以SiH4与H2作为前驱气体,采用射频等离子增强化学气相沉积技术制备了纳米晶硅薄膜.利用Raman散射和红外吸收光谱等技术,对不同氢稀释比条件下薄膜的微观结构和键合特性进行了研究.结果表明,随着氢稀释比增加,薄膜的晶化率明显提高,而氢稀释比过高时,薄膜晶化率呈现减少趋势.红外吸收光谱分析表明,纳米晶硅薄膜中氢的键合模式与薄膜的晶化特性密切相关.随着氢稀释比增加,薄膜中整体氢含量和SiH2键合密度明显减少,而在高氢稀释比条件下,氢稀释比增加导致薄膜中SiH2键合密度和整体氢含量增加.     

光电变色器件用纳米晶氧化钛薄膜的微结构与特性

纳米晶TiO2薄膜在光电变色器件中具有很重要的作用。它的微结构直接影响染料的吸附、光的散射以及电荷输运的特性。因此，探索TiO2薄膜的微结构(如粒径、表面形貌和厚度等)及光电性能是非常有意义的。采用电子束蒸发工艺制备了光电变色器件用纳晶TiO2薄膜，利用原子力显微镜、X射线衍射、俄歇电子能谱等手段对纳米晶TiO2薄膜的表面形貌、结晶状态及组分进行了分析。从理论上研究和讨论了纳米晶TiO2薄膜晶粒尺寸对光电性能的影响，并用量子限制效应解释了吸收光谱峰值波长随粒径减小而发生蓝移的现象。     

氢稀释对高速生长纳米晶硅薄膜晶化特性的影响

以SiH₄与H₂为气源,采用射频等离子体增强化学气相沉积技术,在较高的压强(230Pa)下,研究氢稀释率对纳米晶硅薄膜的生长速率和晶化特性的影响. 实验表明,薄膜的晶化率,晶粒尺寸随着氢稀释率的提高而增加,当氢稀释率为99%,薄膜的晶化率接近70%. 而沉积速率却随着氢稀释率的减小而增加,当氢稀释率从99%减小到95%时,薄膜的沉积速率由0.3nm/s 增加至0.8nm/s. 关键词： 纳米晶硅薄膜 氢稀释 晶化率 硅烷     

ZnO纳米晶/巯基乙酸复合膜的荧光特性

用自组装方法将巯基乙酸(MPA)与ZnO纳米晶薄膜(ZDF)通过共价键偶联到一起,形成纳米晶／巯基乙酸复合膜(ZDF／MPA)。采用发光光谱和XPS电子能谱技术,研究了ZDF／MPA的荧光特性以及它们之间的能量传递机制。研究发现ZDF／MPA中ZnO自由激子发光和束缚激子发光强度随着巯基乙酸的浓度增大而分别呈现不同的非线性减弱关系,当巯基乙酸达到一定的浓度量时,ZnO荧光完全消失。研究表明：ZnO纳米薄膜与MPA之间能够发生成键作用,并且在成键之后发生了能量传递。     

溅射制备纳米晶GaN∶Er薄膜的室温发光特性

利用直流磁控共溅射方法制备了GaN:Er薄膜.X射线衍射结果显示薄膜为纳米多晶结构,根据谢乐公式,计算得到了GaN薄膜晶粒的平均大小为58nm;透射电子显微镜结果显示为非晶基质中镶嵌了GaN纳米颗粒,尺寸在6—8nm之间;紫外可见谱结果表明在500—700nm的可见光范围内,薄膜的平均透过率大于80%,在紫外可见谱基础上,利用Tauc公式计算得到了纳米晶GaN薄膜的光学带隙为322eV;最后,测量了GaN:Er薄膜的室温光致发光谱,获得了Er³⁺离子在554nm处的强烈绿光发射. 关键词： 纳米晶GaN薄膜 3+掺杂')" href="#">Er³⁺掺杂 光学带隙 光致发光     

热处理对富硅氧化硅薄膜中硅纳米晶形成的影响

采用磁控溅射法制备了富硅氧化硅薄膜, 然后分别经过一步热处理、两步热处理和快速热处理制备了镶嵌有硅纳米晶的氧化硅薄膜. 实验结果表明, 在硅含量为～ 42.63 at.%的富硅氧化硅薄膜中, 三种热处理均能形成10¹²/cm²量级的硅纳米晶. 其中在两步热处理中, 硅纳米晶的密度最高, 达到2.2× 10¹²/cm², 并且尺寸均匀、结晶完整性好; 一步热处理后的样品中, 硅纳米晶密度较低, 并且部分纳米晶结晶不充分; 快速热处理后的样品中, 硅纳米晶密度最低、尺寸分布不均匀, 并且存在孪晶结构. 分析认为, 热处理初始阶段的形核过程对纳米晶的密度及微观结构有着重要的影响, 两步热处理中的低温段促进了纳米晶的成核, 有助于形成高密度高质量硅纳米晶.     

Determination of optical properties of SnO2 films

Summary The optical properties of conductive transparent thin films of undoped SnO₂, prepared by using magnetron supttering, were studied by measuring the transmittance and the reflectance between λ=0.25 μm and λ=3μm. The extracted optical constants are interpreted to give values of a direct band gap of the order of 4 eV and of an indirect band gap of the order of 3 eV. Typical SnO₂ films transmit ≈85% of visible light, have sheet resistanceR _∂ (100÷800) Ω_∂ and resistivities of (2.4·10⁻³÷1.8·10⁻²) Ω cm.

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Riassunto Mediante la misura dei valori di transmittanza e di riflettanza per lunghezze d'onda comprese fra 0.25 μm e 3 μm, sono state studiate le proprietà ottiche di film sottili (trasparenti e conduttivi) di SnO₂ non drogato, preparati mediante sputtering. Dai valori così ottenuti sono stati ricavati valori del gap diretto dell'ordine di 4 eV e di quello indiretto dell'ordine di 3 eV. Un film di SnO₂ presenta tipicamente valori della transmittanza intorno all'85%, per luce visibile,R _∂ intorno ai (100÷800) Ω_∂ e resistività fra 2.4·10⁻³ e 1.8·10⁻² Ω cm.

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Резюме Пзмеряя величины пропускания и отражения в области длин волн между λ=0.25 мкм и λ=3 мкм, исследуются оптические свойства проводящих прозрачных тонких пленок нелегированного SnO₂, приготовленных с помощью напыления. Из полученных оптических постоянных извлекаются значения прямой щели, порядка 4 эВ, и непрямой щели, порядка 3 эВ. Типичные пленки SnO₂ пропускают ∼85% видимого света, имеют сопротивлениеR _∂ (100÷800) Ω_∂ и удельные сопротивления в области (2.4·10⁻³÷1.8·10⁻²) Ом·см.

     

Optoelectronic properties of SnO_2 thin films sprayed at different deposition times

This article presents the elaboration of tin oxide(SnO_2) thin films on glass substrates by using a home-made spray pyrolysis system. Effects of film thickness on the structural, optical, and electrical film properties are investigated. The films are characterized by several techniques such as x-ray diffraction(XRD), atomic force microscopy(AFM), ultravioletvisible(UV–Vis) transmission, and four-probe point measurements, and the results suggest that the prepared films are uniform and well adherent to the substrates. X-ray diffraction(XRD) patterns show that SnO_2 film is of polycrystal with cassiterite tetragonal crystal structure and a preferential orientation along the(110) plane. The calculated grain sizes are in a range from 32.93 nm to 56.88 nm. Optical transmittance spectra of the films show that their high transparency average transmittances are greater than 65% in the visible region. The optical gaps of SnO_2 thin films are found to be in a range of 3.64 e V–3.94 e V. Figures of merit for SnO_2 thin films reveal that their maximum value is about 1.15 × 10-4-1?atλ = 550 nm. Moreover, the measured electrical resistivity at room temperature is on the order of 10-2?·cm.     

Microwave magnetic properties of soft magnetic thin films

We review our works that focus on the microwave magnetic properties of metallic,ferrite and granular thin films.Soft magnetic material with large permeability and low energy loss in the GHz range is a challenge for the inforcom technologies.GHz magnetic properties of the soft magnetic thin films with in-plane anisotropy were investigated.It is found that several hundreds of permeability at the GHz frequency was achieved for Co100-xZrx and Co90Nb10 metallic thin films because of their high saturation magneti...     

Oxidation-induced changes in the electro-optical properties of thin copper films

Summary The room temperature oxidation of vapour deposited copper films has been investigated as a function of film thickness and time by the sheet resistance and optical transmittance measurements. An increase of both sheet resistance and transmittance with a tendency to saturation has been observed. Time variation of the sheet resistance shows that the kinetics of oxidation could be described by a model whereby an initial logarithmic oxide growth changes to an inverse logarithmic one as time progresses; the thicker the film, the longer the change-over time. Absorption coefficients of oxidized films show that the resulting oxide is most probably Cu₂O. Evaluation of the oxidized films for possible use as transparent electrode material shows the existence of an optimum thickness value.

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Riassunto Si è studiata l’ossidazione a temperatura ambiente di pellicole di rame depositate per vaporizzazione in funzione dello spessore della pellicola e del tempo mediante la resistenza del foglio e misurazioni di trasmittenza ottica. Si è osservato un aumento sia della resistenza del foglio, sia della trasmittenza con una tendenza alla saturazione. La variazione temporale della resistenza del foglio mostra che la cinetica di ossidazione potrebbe essere descritta da un modello con cui un’iniziale crescita logaritmica dell’ossido cambia in una logaritmica inversa al crescere del tempo; più spessa è la pellicola più lungo è il tempo del cambiamento. I coefficienti di assorbimento delle pellicole ossidate mostrano che l’ossido risultante è molto probabilmente il Cu₂O. La valutazione delle pellicole ossidate per un possibile uso come materiale di elettrodo trasparente mostra l’esistenza di un valore ottimo dello spessore.

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Резюме Исследуется окисление при комнатной температуре пленок меди в зависимости от толщины пленки и времени, используя измерения сопротивления слоя и оптической прозрачности. Наблюдается увеличение сопротивления слоя и прозрачности с тенденцией к насыщению. Временное изменение сопротивления слоя показывает, что кинетика окисления может быть описана с помощью модели, согласно которой начальный логарифмический рост окисла изменяется на обратно логарифмический, когда время увеличивается; для более толстой пленки изменение происходит при больщих временах. Коэффициенты поглощения окисленных пленок показывают, что результирующий окисел представляет Cu₂O. Оценка возможности использования окисленных пленок в качестве прозрачного материала электродов указывает на существование оптимальной толщины пленки.

     

金属银极薄薄膜的光学特性

本文根据可见光区域测量的不同厚度,不同稳定情况下Ag膜透过率光谱响应曲线,结合岛状金属膜有效介质理论,讨论了Ag膜中类自由电子和束缚电子引起的等效洛伦兹振子和带间跃迁随厚度和稳定时间的变化规律。理论计算的透过率曲线与实验符合得很好。比较理论与实验,得到了不同厚度下、不同稳定情况Ag膜的光学常数。     

不同Sb含量p-SnO2薄膜的制备和特性

采用化学气相沉积方法, 利用Sb₂O₃/SnO作为源材料, 在蓝宝石衬底上制备出不同Sb掺杂量的SnO₂薄膜, 并在此基础上制作出p-SnO₂:Sb/n-SnO₂同质p-n 结器件. 研究表明, 随着Sb含量的增加, 样品表面变得平滑, 晶粒尺寸逐渐增大, 且晶体质量有所改善, 发现少量Sb的掺入可以起到表面活化剂的作用. Hall测量结果证实适量Sb的掺杂可以使SnO₂呈现p型导电特性, 当Sb₂O₃/SnO的质量比为1:5时, 其电学参数为最佳值. 此外, p-SnO₂:Sb/n-SnO₂同质p-n结器件展现出良好的整流特性, 其正向开启电压为3.4 V.     

Switching phenomena in CdIn2S4 thin films

Summary Two kinds of switching phenomena in CdIn₂S₄ polycrystalline and amorphous thin films which were prepared by the vacuum evaporation method and the d.c. sputtering method, respectively, were studied. One is the so-called memory switching phenomenon arising from the low resistive filament path. Another is a characteristic switching phenomenon in which the resistivity abruptly changes whenever the ambient temperature reaches a critical value. The switching time is fast and about 100 ns. This switching phenomenon is related to the native defects in the CdIn₂S₄ lattice, because they can be observed in the polycrystalline as well as in the amorphous thin films. Paper presented at the ?V International Conference on Ternary and Multinary Compounds?, held in Cagliari, September 14–16, 1982.     

The optical properties of thin erbium films

The effective dielectric constant, ε′₂, of very thin films of erbium on sodium chloride substrates was determined from measurements of normal incidence reflectance and transmittance in the visible spectrum. ε′₂ showed a maximum which moved to longer wavelengths as the film thickness increased. Electron microscopy revealed that the film islands grew flatter and more irregular with thickness. The shape factor of the islands, F, was calculated by a modified Maxwell-Garnett method and became smaller as the film thickness increased.     

p型导电掺In的SnO2薄膜的制备及表征

采用溶胶-凝胶提拉法成功地制备了p型导电掺In的SnO2薄膜.x射线衍射测试结果表明，掺In的SnO2薄膜保持SnO2的金红石结构.吸收谱测试结果表明，掺In的SnO2禁带宽度为3.8eV.霍尔测量结果表明，空穴浓度与热处理温度有很大的关系，525℃为最佳热处 理的温度.铟锡原子比在0.05—0.20范围内，空穴的浓度与In的含量有直接的关系，并随In含量的增加而增加. 关键词： SnO2 溶胶-凝胶法 p型导电     

Investigation of characteristic properties of Pr-doped SnO2 thin films

In the present work, an investigation study on the crystal structure, surface morphology, electrical conductivity and optical transparency of spray-deposited Pr-doped SnO₂ was made as a function of Pr doping content. The X-ray diffraction studies indicated that the films were grown at the (2 1 1) preferential orientation. The values of crystallite size and strain were determined using Williamson–Hall method and they varied between 71.47 and 208.76 nm, and 1.98 × 10^?3 – 2.78 × 10^?3. As seen from Scanning Electron Microscope micrographs, the films were composed of homogenous dispersed pyramidal-shaped grains. The n-type conductivity of films was confirmed with Hall Effect measurements, and the best electrical parameters were found for 3 at.% Pr doping level. The highest optical band gap and transmittance values were observed for undoped SnO₂ sample. The highest figure of merit (Φ), which is a significant parameter to interpret the usage efficiency of conductive and transparent materials in the optoelectronic and solar cell applications, was calculated to be 2.85 × 10^?5 Ω^?1 for 1 at.% Pr doping content. As a result of this study, it may be concluded that Pr-doped SnO₂ films with above properties can be used as a transparent conductor in various optoelectronic applications.