利用电子束光刻制备晶面依赖的硅纳米结构

利用电子束光刻和各向异性湿法腐蚀技术,在(100)SOI衬底上成功地制备出晶面依赖的硅纳米结构.这项技术利用了硅的不同晶面在碱性腐蚀溶液中具有不同腐蚀速率的特性.纳米结构脊部宽度的最小尺寸可以达到10nm以下.扫描电镜和原子力显微镜的观察表明,利用这种方法制备出来的纳米结构具有很好的重复性,而且表面光滑.     

各向异性腐蚀制备纳米硅尖

采用KOH溶液各向异性腐蚀单晶硅的方法制备高纵横比的纳米硅尖,研究了腐蚀溶液的浓度、添加剂异丙醇(IPA)对硅尖形状的影响。设计了硅尖制作的工艺流程,制备了形状不同、纵横比值为0.52～2.1的硅尖,并结合晶面相交模型,提出了硅尖晶面的判别方法,讨论了实验中出现的{411}和{331}晶面族两种硅尖晶面类型,实验结果和理论分析相一致。通过分析腐蚀溶液的质量分数和添加剂对{411}、{331}晶面族腐蚀速度的影响,得到了制备高纵横比纳米硅尖的工艺参数。实验结果表明:当正方形掩模边缘沿<110>晶向时,在78℃、质量分数40的KOH溶液中腐蚀硅尖,再经980℃干氧氧化3h进行锐化削尖,可制备出纵横比大于2、曲率半径达纳米量级的硅尖阵列。     

用于X射线闪烁屏的硅微通道阵列整形技术

为制备用于X射线闪烁屏的高开口面积比硅微通道阵列,研究了四甲基氢氧化铵(TMAH)溶液温度和质量分数对硅(100)晶面和(110)晶面腐蚀速率的影响.通过金相显微镜观测硅微通道端面尺寸并计算腐蚀速率,分析了硅(100)晶面和(110)晶面腐蚀速率比对硅微通道阵列孔形的影响,探讨了TMAH溶液温度和质量分数与硅微通道阵列开口面积比的关系.研究表明,硅(100)晶面和(110)晶面的腐蚀速率比是影响硅微通道阵列开口面积比的主要因素.当硅(100)晶面与(110)晶面腐蚀速率比大于√2时,得到具有高开口面积比的正方形硅微通道阵列.使用质量分数为1％的TMAH溶液在40℃的溶液温度下,制备出开口面积比大于81％的正方形硅微通道阵列.通过高温填充CsI (TI)制备出基于硅微通道的X射线闪烁屏,X射线成像结果表明通道整形技术有助于提高闪烁屏的性能.     

ZnO纳米棒的图形化生长及其场发射特性

介绍了用氢离子注入技术和阳极腐蚀方法在硼掺杂p-(100)型硅晶片上制备图形化的纳米硅(SiNC)薄膜工艺,并在这种图形化衬底上成功生长了图形化的ZnO纳米棒.场发射测试表明制备的ZnO纳米棒具有良好的场发射性能,即具有较低的开启电场和阈值电场,较高的发射点密度.     

ZnO纳米棒的图形化生长及其场发射特性

介绍了用氢离子注入技术和阳极腐蚀方法在硼掺杂p-(100)型硅晶片上制备图形化的纳米硅(SiNC)薄膜工艺,并在这种图形化衬底上成功生长了图形化的ZnO纳米棒.场发射测试表明制备的ZnO纳米棒具有良好的场发射性能,即具有较低的开启电场和阈值电场,较高的发射点密度.     

纳米硅层状薄膜及其p-i-n太阳能电池的研制

通过等离子体增强化学气相沉积(PECVD)法分别制备了本征、掺磷和掺硼的氢化纳米硅薄膜(nc-Si:H),并制备出纳米硅复合层状薄膜.对薄膜样品进行了喇曼(Raman)散射谱,X射线衍射等分析测试.结果表明:掺杂元素对纳米硅薄膜的晶态比和晶粒大小存在不同程度的影响;通过薄膜表面衍射(XRD)可得到硅的(111),(220)和(311)三个晶面衍射峰;并在制得的纳米硅复合层状薄膜的基础上,制备了结构为Al/ITO/n+-nc-Si:H/i-nc-Si:H/p-c-Si/Al/Ag的太阳能电池.该电池的开路电压、短路电流和填充因子与非晶硅太阳电池相比,均得到很大的提高.     

一维纳米硅光子晶体的制备与优化

采用双槽电化学腐蚀法制备了纳米多孔硅,主要研究了腐蚀时间和腐蚀电流对重掺杂p型(100)硅衬底上制备的多孔硅层有效光学厚度的影响,采用U-4100光谱仪、场发射扫描电子显微镜(FESEM)技术对所制备的多孔硅光子晶体的结构和有效光学厚度进行了分析表征。研究结果表明,通过合理地选择腐蚀时间和腐蚀电流,可以比较精确地制备特定有效光学厚度的多孔硅薄膜,此方法可广泛应用于纳米多孔硅光子晶体的制备中。     

纳米硅层状薄膜及其p-i-n太阳能电池的研制

通过等离子体增强化学气相沉积(PECVD)法分别制备了本征、掺磷和掺硼的氢化纳米硅薄膜(nc-Si:H),并制备出纳米硅复合层状薄膜.对薄膜样品进行了喇曼(Raman)散射谱,X射线衍射等分析测试.结果表明:掺杂元素对纳米硅薄膜的晶态比和晶粒大小存在不同程度的影响;通过薄膜表面衍射(XRD)可得到硅的(111),(220)和(311)三个晶面衍射峰;并在制得的纳米硅复合层状薄膜的基础上,制备了结构为Al/ITO/n -nc-Si:H/i-nc-Si:H/p-c-Si/Al/Ag的太阳能电池.该电池的开路电压、短路电流和填充因子与非晶硅太阳电池相比,均得到很大的提高.     

ZnO纳米棒的图形化生长及其场发射特性

介绍了用氢离子注入技术和阳极腐蚀方法在硼掺杂p-(100)型硅晶片上制备图形化的纳米硅(SiNC)薄膜工艺，并在这种图形化衬底上成功生长了图形化的ZnO纳米棒. 场发射测试表明制备的ZnO纳米棒具有良好的场发射性能，即具有较低的开启电场和阈值电场，较高的发射点密度.     

基于硅模具制作的纳米裂纹及应变传感器

纳米裂纹制造技术作为一种非传统的纳米加工技术被应用于纳米线条、纳流控芯片和传感器等众多研究领域,然而纳米裂纹生成的随机性及其图案的不确定性限制了该项技术的发展.利用硅模具以及二次倒模工艺,在聚二甲基硅氧烷(PDMS)基底表面制作相互平行且分布均匀的金纳米裂纹.硅模具上带有利用硅各向异性腐蚀工艺加工出的V型沟槽结构,通过...     

硅基太阳电池的表面纳米织构及制备

综述了用于硅基太阳电池高效陷光的四种表面纳米织构,即金属纳米颗粒、纳米线、纳米锥和纳米孔。相对于其他三种表面纳米织构,纳米孔具有更好的结构特性和陷光能力。详细介绍了各种表面纳米织构的制备方法,如金属薄膜退火、金属诱导化学腐蚀、干法刻蚀、深紫外光刻和纳米球光刻等。通过表面纳米织构提高效率是太阳电池领域的重点研究内容。表面纳米织构以其优异的光电特性,将在未来高效光伏器件中得到重要应用。     

A system for precision reactive ion-beam etching of nanostructures for field-emission devices

An system for precision selective ion-beam etching of nanostructures for field-emission devices is developed. The system is equipped with a Radikal-M160 multibeam ion source with a cold cathode and closed electron drift forming the ion beam of the working substance with a diameter of 160 mm and a microwave input for the supply of the microwave bias to the treated substrates. Technological possibilities of the system are investigated experimentally. The advantages of simultaneous ion-beam and microwave etching of the nanostructures are shown. The processes of precision etching of nanostructures through a mask up to 1 μm thick with diameters of orifices of 20–30 nm (aspect ratio of the structures of the mask ∼50: 1) are carried out.     

Sacrificial film-assisted nanoimprint lithography

We have demonstrated a nanopattterning technique that combines the use of sacrificial film and nanoimprint lithography. The sacrificial film serves as a ‘transient substrate’ during the nanoimprinting steps. The use of a sacrificial film improves the patterning yield significantly because the de-molding is achieved by etching off the sacrificial film, instead of a mechanical de-molding as in conventional nanoimprint lithography. This patterning technique is an easy method to build up multilayer structure from a single type of polymer. The method is also highly versatile; both substrate supported and freestanding nanostructures can be easily achieved by this technique.     

刻蚀辅助激光灰度改性技术制备硅基三维微结构

硅基三维微纳结构在红外成像与探测方面具有重要的应用价值。然而,受加工技术的限制,硅基复杂面型三维微纳结构的制备仍然是一个难题。本文提出了利用刻蚀辅助激光灰度改性技术制备硅基三维微纳结构。利用激光改性制备的硅的氧化层作为刻蚀掩膜,经过刻蚀实现灰度图形向衬底的转移。研究发现,氧化层的抗刻蚀能力可以通过激光加工参数进行调控,例如,激光功率和扫描间距。通过编程化设计的局部调控的抗刻蚀氧化层图形,刻蚀后实现了台阶状、斜面及曲面复杂三维微结构的可控制备。另外,验证了该技术在特殊面型硅基微光学器件制备中的可行性。     

Nanoscale structure formation by plasma etching

Process of isotropic plasma etching of polysilicon to form nanostructures has been developed and optimized. Dependences of the technological characteristics of the isotropic plasma etching process of polysilicon on its operational parameters have been obtained. The results were to form nanowire silicon field effect transistors and a sensitive vibro-resonant nanoelement for an atom mass sensor.     

3D Out‐of‐Plane Rotational Etching with Pinned Catalysts in Metal‐Assisted Chemical Etching of Silicon

Pinned structures in conjunction with shaped catalysts are used in metal‐assisted chemical etching (MACE) of silicon to induce out‐of‐plane rotational etching. Sub‐micro‐ and nanostructures are fabricated in silicon, which include scooped‐out channels and curved subsurface horns, along with vertically oriented thin metal structures. Five different etching modes induced by catalyst and pinning geometry are identified: 1) fully pinned–no etching, 2) rotation via twist, 3) rotation via delamination, 4) in‐plane bending, and 5) swinging. The rotation angle is roughly controlled through catalyst geometry. The force and pressure experienced by the catalyst are calculated from the deformation of the catalyst and range between 0.5–3.5 μN and 0.5–3.9 MPa, respectively. This is a new, simple method to fabricate 3D, heterogeneous sub‐micro‐ and nanostructures in silicon with high feature fidelity on the order of tens of nanometers while providing a method to measure the forces responsible for catalyst motion during MACE.     

Structural and optical properties of silicon nanowires synthesized by Ag-assisted chemical etching

Metal-assisted chemical etching (MACE) of silicon in an aqueous solution of hydrofluoric acid and hydrogen peroxide is established for the fabrication of large-area uniform silicon nanowire (SiNW) arrays. The effect of the silver catalyst layer thickness on the morphology of the synthesized nanostructures and nanowires is investigated. Atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM) reveal that the morphology of the fabricated silicon nanostructures remarkably depends on the catalyst layer thickness, and an optimum layer thickness is necessary for the fabrication of SiNWs. Also the effect of different etching times on the structural and optical properties of the fabricated SiNWs is investigated. FESEM showed a linear increment of the nanowire length and slight diameter changes through different etching times. The ultralow reflectance of SiNWs in the absorption region through the measurement of specular and diffuse reflectance showed that with increase in the etching time, the total reflectance remarkably decreases. A broadband visible photoluminescence (PL) emission from these wires was observed, and it could be stated that the silicon nanocrystals (SiNCs) are mostly responsible for the PL emission. The SiNC sizes were determined by an analytical model through a frequency shift in the Raman spectrum. The synthesized optically-active SiNWs could, therefore, be considered as a promising candidate for a new generation of nanoscale opto-electronic devices.     

Integration of SiC-1D nanostructures into nano-field effect transistors

We report on the integration and the electrical transport properties of silicon carbide-based one-dimensional nanostructures into field effect transistors. Different kinds of SiC-based 1D nanostructures have been used: 3C– and 4H–SiC nanowires obtained by a plasma etching process, Si–SiC core–shell nanowires and SiC nanotubes both obtained by a carburization route of silicon nanowires.     

Fabrication of periodic square arrays by angle-resolved nanosphere lithography

We investigate the fabrication of periodic square arrays of solid gold islands by angle-resolved nanosphere lithography (ARNSL) in conjunction with thermal evaporation and etching. By varying θ (the tilt angle between the direction of gold deposition beam and the substrate surface normal) and ? (the substrate rotation angle about the beam axis), adjacent islands on a deposited hexagonal gold array will have a constant and periodic difference in height. Upon etching, this height bias will result in the shorter structures being removed to produce an array with a different symmetry from the original hexagonal symmetry of the parent mask. By depositing at three directions of ? = 0°, 120° and −120° with a constant θ = 20°, experimental results show that deposited two-dimensional gold periodic arrays will have a measurable difference in height between adjacent islands. Etching of the resulting patterns produced periodic near-square arrays with triangular nanostructures. Thus the combination of ARNSL and etching can allow selective periodic nanostructures to be removed, increasing the diversity of array symmetries available through nanosphere lithography.