二维金纳米阵列制备及其光学响应

有序贵金属纳米结构由于其本身所特有的光学响应及灵活调控能力,在微纳光电子材料与器件研究领域得到了广泛应用。在众多相关研究中,如何实现金（Au）纳米周期结构的大面积快速制备是人们关心的重要问题之一。采用纳米球自组装刻蚀方法,在大孔周期结构模板内部成功制备了新型二维Au纳米阵列,并有效避免了杂散Au纳米颗粒的产生。通过进一步的工艺优化和参量控制,实现了Au纳米颗粒尺寸的灵活调控,并探讨了其结构形成的物理机理。光学测试研究结果揭示了二维Au纳米阵列的表面等离子体吸收与散射响应,并证明其在近红外飞秒脉冲激励下具有显著的双光子吸收（饱和）效应。该研究结果在太阳能电池,光开关及材料微纳制备等领域具有潜在应用。     

金纳米粒子作掩模的硅纳米柱阵列的加工

利用自组装的方法在硅基片表面形成一层均匀的金纳米粒子掩模,分析了偶联剂对自组装的影响,以金纳米粒子作掩模进行反应离子刻蚀,研究了刻蚀时间对硅纳米柱阵列的影响,提供了一种简单、便宜并且有效的在硅基底上大面积形成纳米柱阵列的纳米加工方法。实验中发现,超过一定刻蚀时间时,有过刻蚀现象发生,在120 s刻蚀时间下,得到了直径小于20 nm,深宽比高达10∶1以上规则、致密、大面积分布的硅纳米柱或硅纳米锥状结构。     

自组装金纳米粒子薄膜AFM研究

以化学还原法制备了金胶体,采用静电吸附自纽装法在单晶硅片表面制备了金纳米粒子薄膜,采用原子力显微镜分析了薄膜的表面形貌与结构。     

基于自组装金纳米颗粒的化学电阻传感器

通过Au—S键的自组装作用,制备了不同功能单体修饰的金纳米颗粒(AuNP),采用扫描电子显微镜(SEM)对制备材料的微观形貌进行了表征,并使用滴铸法制成了电阻式气体传感器,对其气敏性能进行了测试.实验结果表明,基于11-巯基-1-十一醇(MUD)功能化的AuNP化学电阻传感器的气敏性能最佳,在室温条件下,对1×10-6...     

基于介电泳机理的金纳米颗粒传感器装配方法

研究了一种基于介电泳机理的金纳米颗粒传感器装配方法。在分析介电泳工作原理的基础上,利用Comsol Multiphysics仿真软件,对平面微电极条件下所产生的空间电场进行了建模仿真,研究了金纳米粒子极化模型及相关介电泳频谱特性。设计加工了基于光刻标准工艺和引线键合技术的平面微电极阵列,构建了具有三维位移平台和视频监控装置的介电泳装配实验平台。以250nm金颗粒为实验对象,在理论分析基础上,完成了在微电极阵列上的介电泳组装实验研究,并通过电特性测量验证了组装结果。实验结果表明:金纳米颗粒的介电泳组装效果与介质溶液的电导率、电场频率和幅度、金纳米粒子浓度、电极间隙及作用时间有关,在适宜的条件下,采用介电泳技术可实现对金纳米颗粒的有效操控和纳米器件装配,该方法为纳米传感器的制造提供了一种有效途径。     

自组装银纳米环等离激元生物传感器的制备与光学性质

在过去的十几年中,衍射耦合超窄共振已经发展成为一个独立的、快速扩展的研究领域。这种共振模式通常被称为表面晶格共振,具有体积小、易集成、低功耗等特点。设计了一种性能优异且可规模化生产的表面晶格共振折射率传感器。利用时域有限差分法进行了仿真,对结构的光学性能进行了研究。采用纳米球光刻技术以及纳米压印技术,制备出大面积、高质量的银纳米环阵列,结构的灵敏度为663 nm/RIU,品质因数为9.2。通过改变结构的几何参数,不仅能实现对共振波的调谐,同时还能提高折射率灵敏度。所提传感器在生物传感领域具有潜在的应用前景。     

基于阳极氧化铝模板的金属纳米孔阵列膜制备

以0.3 mol/L草酸为电解液,在40 V直流电压、0～5℃下采用二步阳极氧化法制备了纳米多孔阳极氧化铝模板。用射频磁控溅射法在阳极氧化铝模板表面制备了金属铝膜。SEM分析结果表明:金属膜复制了阳极氧化铝模板形貌,具有纳米孔有序阵列结构;金属膜的孔径受控于溅射功率和时间,功率30 W下沉积10 min约为68 nm,32 W下10 min约为58 nm,32 W下15 min约为25 nm。     

银纳米颗粒的局域表面等离子体共振传感

采用微波法合成银纳米颗粒,通过化学自组装技术将银纳米颗粒吸附在玻璃基片上,制备了银纳米颗粒的局域表面等离子体传感器。在纯水中,紫外可见光消光谱表明局域表面等离子体共振位于428nm处。随外界折射率增加,共振峰发生红移,其折射率灵敏度达到173±6nm/RIU。在350oC温度下退火处理后,改变银颗粒在基片上的形貌,峰位发生约65nm的红移,灵敏度下降约20%。理论分析表明,银纳米颗粒形状和基底的相互作用影响折射率传感的波长响应和灵敏度特性。     

表面等离子体近场光刻制作二维纳米阵列

重点介绍了采用表面等离子体增强效应的近场光刻制作亚微米结构的二维点阵图形的技术。在研究亚波长纳米孔阵列超透射现象基本原理的基础上,应用有限差分时域(FDTD)算法数值模拟了周期性孔阵列的电场强度分布,讨论了纳米孔阵列所激发的表面等离子体激元提高近场光刻分辨率的微观机制。以金膜上的亚波长纳米孔阵列作为掩模版进行了接触式曝光实验,实际制作出了光刻胶的亚波长二维点阵图形,点阵图形的直径约为300nm,周期约为700nm。这种新型的微纳加工技术具有应用简单、成本低等特点,在大规模二维纳米点阵的制作方面有一定的应用潜力。     

硅基多孔氧化铝薄膜的解理断裂特性

近年来,人工制备量子点、量子线等纳米结构材料引起了广泛关注。通常的制备方法有电子束刻蚀、离子束刻蚀、X射线刻蚀、电子全息成像刻蚀等。这类方法所能达到的最低尺度为≥10nm[1]。而阳极氧化多孔氧化铝的最小孔径可达1nm[2],其特征参数如孔径(1～300nm)、孔长(10～300nm)及孔密度(108～1011cm-2)都可以用选择不同腐蚀电压的方法来加以控制,而且孔的长度直径比可达1000以上,所以,作为模板,多孔氧化铝薄膜在纳米材料制备方面有其独到之处。但是,多孔氧化铝薄膜容易卷曲、断裂,这一缺点影响它在纳米工业中的应用。本文利用电镜研究阳极氧…     

Formation and properties of thin-film composites vanadium oxide/porous anodic aluminum oxide

Nanostructured thin-film composites vanadium oxide/porous anodic aluminum oxide (VO/PAO) were investigated. Thin layers of vanadium oxide were formed by sol-gel deposition from the solution of vanadium isopropoxide in isopropanol with subsequent annealing in Ar atmosphere at 500°C. As a substrate, porous anodic aluminum oxide and Si/SiO₂ with PAO and without it were used. The orienting effect of PAO on the formation of the vanadium oxide layer has been established. Using the techniques of X-ray diffraction and electron microscopy, the formation of the crystalline vanadium dioxide VO₂ phase, the orientation of the grains, which correlates with the morphology of the PAO substrate, has been established. The influence of electrolyte and stresses during the filling of the pores of aluminum oxide on the formation of grains, nanoclusters, and agglomerates of vanadium oxide is analyzed. Electrical properties of the nanostructured vanadium oxide layer were investigated. The characteristic of electrical resistance indicate the reversible insulator-metal phase transition in vanadium dioxide. The capacitances-voltage characteristics of the Al/VO/PAO/Al sandwich structures had an asymmetric character with an increase in capacitance upon increasing the negative bias voltage on vanadium oxide. This effect is determined by the phase transition insulator-metal under the influence of electric field. In addition, injection of electrons from the Al electrode or their extraction from vanadium oxide as well as recharging of the VO/PAO interface states can exert the influence. The mechanism for vanadium dioxide formation on the orienting substrate made of porous anodic aluminum oxide is proposed.     

Radial microstructure and optical properties of a porous silicon layer by pulse anodic etching

This paper investigates the radial refractive index and optical and physical thicknesses of porous silicon (PS) layers prepared by pulse etching by means of reflectance spectroscopy,photoluminescence spectroscopy and scanning electron microscopy(SEM).The relationship between the radial refractive index and optical thickness of the PS sample and the position away from the etched centre along the radial direction has been analyzed in detail. With the position farther away from the etched centre,the SEM image shows that the physical thickness of the PS sample decreases slowly,whereas intensely decreases from 2.48 to 1.72μm near the edge at a distance of 58μm.Moreover,the radial refractive index increases,indicating that the porosity becomes smaller.Meanwhile,the reflectance spectra exhibit the less intense interference oscillations,which mean that the uniformity and interface smoothness of the PS layers become worse,and the envelope curves of photoluminescence spectra exhibit a trend of blue-shift,indicating a reduction in nanocrystal dimensions.The PS micro-cavity is prepared to study the radial optical properties of the PS layer,and the results verify that the uniformity and smoothness of the PS layer in the centre are better than those at the edge.     

通过脉冲腐蚀形成的多孔硅薄膜的径向微结构和光学特性研究

使用反射光谱、光致发光光谱和SEM研究了通过脉冲腐蚀形成的多孔硅薄膜的径向折射率、光学和物理厚度。详细分析了沿径向方向多孔硅薄膜的径向折射率(n)和光学厚度(nd)与腐蚀中心之间的关系。实验结果表明：随着远离腐蚀中心,SEM图像表明：多孔硅样品的物理厚度缓慢变小,在腐蚀边缘,在径向58μm距离里,薄膜的物理厚度从2.48μm减少到1.72μm;此外,径向折射率n增加,即多孔度变小,同时,反射光谱强度显示出干涉振荡减弱,这意味着多孔硅薄膜的均匀性和界面的平整度变坏。光致发光谱的包络线显示蓝移的趋势,显示纳米微粒的尺寸减少。多孔硅微腔被制备用来研究多孔硅膜的径向光学特性,结果证实：在腐蚀中心,多孔硅膜的均匀性比边缘好。     

硅基多孔氧化铝薄膜微结构的TEM研究

阳极氧化多孔氧化铝薄膜(anodicporousaluminafilm,APA)作为模板的应用已引起广泛关注。它的优点在于其主要的特征参数如孔径(1～300nm)、孔长(10～3000nm)及孔密度(108～1011cm-2)都可以用选择不同腐蚀电压的方法来加以控制,孔的长度直径比可达1000以上[1],而且在理想的APA膜中,孔阵列规则排列为蜂巢状六方结构[2]。这一特点为大面积原位合成规则排列纳米量子点/线材料提供了重要保证。考虑到和当前主流硅集成半导体工业相匹配,硅基多孔氧化铝薄膜(Si-basedanodicporousaluminafilm,APA/Si)的应用已见报道[3,4]。我们研究发现当孔径小…     

Self-organized growth mechanism for porous aluminum anodic oxide

Likely mechanisms of the self-organization observed in the growth of porous aluminum anodic oxide are discussed. A mechanism that includes physical and chemical processes occurring in the initial stage is put forward by considering the distribution of an applied voltage between three main components of the electrochemical system: a growing oxide layer; a Helmholtz layer at the oxide-electrolyte interface; and a Gouy-Chapman space-charge layer, which extends to the quasi-neutral electrolyte region. It is found that the transformation of the Helmholtz layer is due to self-organization effects in the Gouy-Chapman layer. The cell size of the porous oxide is shown to vary as Gouy-Chapman layer thickness, which in turn depends on the temperature, concentration, and composition of the electrolyte. The theoretical results obtained are in good agreement with previous experiments.     

Terbium luminescence in alumina xerogel fabricated in porous anodic alumina matrix under various excitation conditions

Terbium-doped alumina xerogel layers are synthesized by the sol-gel method in pores of a porous anodic alumina film 1 μm thick with a pore diameter of 150–180 nm; the film is grown on a silicon substrate. The fabricated structures exhibit terbium photoluminescence with bands typical of trivalent terbium terms. Terbium X-ray luminescence with the most intense band at 542 nm is observed for the first time for such a structure. Morphological analysis of the structure by scanning electron microscopy shows the presence of xerogel clusters in pore channels, while the main pore volume remains unfilled and pore mouths remain open. The data obtained confirm the promising applications of fabricated structures for developing matrix converters of X-rays and other ionizing radiations into visible light. The possibilities of increasing luminescence intensity in the matrix converter are discussed.     

模板合成法制备ZnO纳米线的研究

在草酸和硫酸电解液中分别制备了孔径为40 nm和20 nm左右的多孔氧化铝模板,用直流电化学沉积的方法,在模板孔洞内电解沉积Zn,对其进行高温下的氧化,可得到高度有序的ZnO纳米线.扫描电子显微镜观察显示,多晶的Zn纳米线均匀地填充到多孔氧化铝六角排布的孔洞里,直径与模板孔径相当.X射线衍射谱测量证实,制备的Zn纳米线和ZnO纳米线均为多晶结构,并且对比了模板孔径对纳米线结构的影响.测量了多孔氧化铝厚膜和Zn/Al2O3组装体的吸收光谱,发现其在红外波段的吸收系数有逐渐降低的趋势.     

Synthesis and optical properties of Ni-doped zinc oxide nanoparticles for optoelectronic applications

Nanocrystalline undoped and nickel doped zinc oxide (Zn1-xNixO, x=0.00, 0.01) powders are successfully synthesized by a simple and low-temperature "auto-combustion method". The microstructural and optical absorption and emission properties of the as-prepared samples are obtained using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infra-red spectrometer (FTIR), UV-visible and photoluminescence (PL). The structure study confirms the formation of the hexagonal wurtz...     

Study of the morphology and optical properties of anodic oxide layers on InAs (111)III

The effect of the electrolyte composition on the surface morphology and the dispersion dependences of the refractive index and extinction coefficient of ～20-nm-thick anodic layers on InAs (111)III substrates is studied by atomic force microscopy and spectral ellipsometry. It is shown that oxidation in electrolytes with different acidities does not modify the surface morphology of the initial InAs substrates. The films formed upon oxidation exhibit close dispersion dependences, despite the difference in the chemical composition between the films. This makes possible the high-precision monitoring of the thickness of anodic layers on InAs substrates by means of ellipsometry with the optical model of a single-layer isotropic film on an absorbing substrate.