The silicon nanoporous pillar array （Si-NPA） is synthesized by using hydrothermal etching method, and the electron field emission properties are studied. The results show that Si-NPA has a low turn-on field of 1.48...The silicon nanoporous pillar array （Si-NPA） is synthesized by using hydrothermal etching method, and the electron field emission properties are studied. The results show that Si-NPA has a low turn-on field of 1.48 V/μm at the emission current of 0.1 μA and its field emission is relatively stable. The field emission enhancement of Si-NPA is believed to originate from its unique morphology and structure. Our finding demonstrates that the Si-NPA is a promising candidate material for field emission applications.展开更多
Arrays of silicon micro\|tips were made by etching the p\|type (1 0 0) silicon wafers which had SiO 2 masks with alkaline solution. The density of the micro\|tips is 2×10 4 cm -2 . The Scanning Elect...Arrays of silicon micro\|tips were made by etching the p\|type (1 0 0) silicon wafers which had SiO 2 masks with alkaline solution. The density of the micro\|tips is 2×10 4 cm -2 . The Scanning Electron Microscope (SEM) photos showed that the tips in these arrays are uniform and orderly. The CN x thin film, with the thickness of 1.27μm was deposited on the silicon micro\|tip arrays by using the middle frequency magnetron sputtering technology. The SEM photos showed that the films on the tips are smoothly without particles. Keeping the sharpness of the tips will benefit the properties of field emission. The X\|ray photoelectron spectrum (XPS) showed that carbon, nitrogen and oxygen are the three major elements in the surfaces of the films. The percents of them are C: 69.5 %, N: 12.6 % and O: 17.9 %. The silicon arrays coated with CN x thin films had shown a good field emission characterization. The emission current intensity reached 3.2 mA/cm 2 at 32.8 V/μm, so it can be put into use. The result showed that the silicon arrays coated with CN x thin films are likely to be good field emission cathode. The preparation and the characterization of the samples were discussed in detail.展开更多
To understand the deformation and removal mechanism of material on nano-scale at ultralow loads,a systemic study on AFM micro/nano-machining on single crystal ailicon is conducted. The results indicate that AFM nano- ...To understand the deformation and removal mechanism of material on nano-scale at ultralow loads,a systemic study on AFM micro/nano-machining on single crystal ailicon is conducted. The results indicate that AFM nano- machining has a precisely dimensional controllability and a good surface quality on nanometer scale.A SEM is adopted to observe nano-machined region and chips,the results indicate that the material removal mechanisms change with the applied normal load. An XPS is used to analyze the changes of chemical composition inside and outside the nano-machined region respectively.The nano-indentation which is conducted with the same AFM diamond tip on the machined region shows a big discrepancy compared with that on the macro-scale. The calculated results show higher nano-hardness and elastic modulus than normal values .This phenomenon on be regarded as the indentation size effect(ISE).展开更多
面向原子力显微镜(atomic force microscope,AFM)探针的应用需求,提出一种基于硅尖的垂直取向碳纳米管(carbon nanotubes,CNTs)制备方法。首先,通过优化掩膜设计和KOH湿法腐蚀工艺,制备了高度约为6μm的硅尖阵列;然后,采用图案化催化剂...面向原子力显微镜(atomic force microscope,AFM)探针的应用需求,提出一种基于硅尖的垂直取向碳纳米管(carbon nanotubes,CNTs)制备方法。首先,通过优化掩膜设计和KOH湿法腐蚀工艺,制备了高度约为6μm的硅尖阵列;然后,采用图案化催化剂定位投放技术,在硅尖顶端实现了铁蛋白分子的选择性附着;最后,通过热化学气相沉积(chemical vapor deposition,CVD)法,在优化的工艺参数下,成功在硅尖上生长出直径约16~20 nm、垂直取向的单根碳纳米管。扫描电子显微镜(scanning electron microscopy,SEM)和透射电子显微镜(transmission electron microscopy,TEM)表征结果显示,所制备的CNTs结构均匀且结晶度良好;拉曼光谱分析进一步证实其具有高度石墨化特性。研究结果可为高性能AFM探针的制备提供可行的技术方案,具有重要的应用价值。展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 10574112, and the Natural Science Foundation of Henan Province under Grant No 411011800.
文摘The silicon nanoporous pillar array （Si-NPA） is synthesized by using hydrothermal etching method, and the electron field emission properties are studied. The results show that Si-NPA has a low turn-on field of 1.48 V/μm at the emission current of 0.1 μA and its field emission is relatively stable. The field emission enhancement of Si-NPA is believed to originate from its unique morphology and structure. Our finding demonstrates that the Si-NPA is a promising candidate material for field emission applications.
文摘Arrays of silicon micro\|tips were made by etching the p\|type (1 0 0) silicon wafers which had SiO 2 masks with alkaline solution. The density of the micro\|tips is 2×10 4 cm -2 . The Scanning Electron Microscope (SEM) photos showed that the tips in these arrays are uniform and orderly. The CN x thin film, with the thickness of 1.27μm was deposited on the silicon micro\|tip arrays by using the middle frequency magnetron sputtering technology. The SEM photos showed that the films on the tips are smoothly without particles. Keeping the sharpness of the tips will benefit the properties of field emission. The X\|ray photoelectron spectrum (XPS) showed that carbon, nitrogen and oxygen are the three major elements in the surfaces of the films. The percents of them are C: 69.5 %, N: 12.6 % and O: 17.9 %. The silicon arrays coated with CN x thin films had shown a good field emission characterization. The emission current intensity reached 3.2 mA/cm 2 at 32.8 V/μm, so it can be put into use. The result showed that the silicon arrays coated with CN x thin films are likely to be good field emission cathode. The preparation and the characterization of the samples were discussed in detail.
基金This project is supported by National Natural ScienceFoundation of China (No.59835180) and Science andTechnology Foundatio
文摘To understand the deformation and removal mechanism of material on nano-scale at ultralow loads,a systemic study on AFM micro/nano-machining on single crystal ailicon is conducted. The results indicate that AFM nano- machining has a precisely dimensional controllability and a good surface quality on nanometer scale.A SEM is adopted to observe nano-machined region and chips,the results indicate that the material removal mechanisms change with the applied normal load. An XPS is used to analyze the changes of chemical composition inside and outside the nano-machined region respectively.The nano-indentation which is conducted with the same AFM diamond tip on the machined region shows a big discrepancy compared with that on the macro-scale. The calculated results show higher nano-hardness and elastic modulus than normal values .This phenomenon on be regarded as the indentation size effect(ISE).
文摘面向原子力显微镜(atomic force microscope,AFM)探针的应用需求,提出一种基于硅尖的垂直取向碳纳米管(carbon nanotubes,CNTs)制备方法。首先,通过优化掩膜设计和KOH湿法腐蚀工艺,制备了高度约为6μm的硅尖阵列;然后,采用图案化催化剂定位投放技术,在硅尖顶端实现了铁蛋白分子的选择性附着;最后,通过热化学气相沉积(chemical vapor deposition,CVD)法,在优化的工艺参数下,成功在硅尖上生长出直径约16~20 nm、垂直取向的单根碳纳米管。扫描电子显微镜(scanning electron microscopy,SEM)和透射电子显微镜(transmission electron microscopy,TEM)表征结果显示,所制备的CNTs结构均匀且结晶度良好;拉曼光谱分析进一步证实其具有高度石墨化特性。研究结果可为高性能AFM探针的制备提供可行的技术方案,具有重要的应用价值。
基金supported by Key Laboratory Open Fund of Ultra Precision Machining Technology of CAEP(KF13006)Research Fund for the Doctoral Program of Higher Education of China(20120191120022)
