Carbon nanotube atomic force microscopy tips: Direct growth by chemical vapor deposition and application to high-resolution imaging
Carbon nanotube atomic force microscopy tips: Direct growth by chemical vapor deposition and application to high-resolution imaging
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DOI：
10.1073/pnas.050498597
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发表时间：
2000-04-11
影响因子：
11.1
通讯作者：
Lieber, CM
中科院分区：
文献类型：
--
作者：
Cheung, CL;Hafner, JH;Lieber, CM
碳纳米管是潜在的理想的原子力显微镜探针，因为它们可以具有小至一纳米的直径，具有稳健的机械性能，并且可以在尖端用化学和生物探针进行特定功能化。该通信描述了通过化学气相沉积（CVD）使用沉积在商业硅悬臂尖端组件上的乙烯和铁催化剂直接生长碳纳米管尖端的方法。扫描电子显微镜和透射电子显微镜的测量表明，多壁纳米管和单壁纳米管尖端可以通过CVD生长条件中的可预测的变化来生长。力-位移测量的提示表明，他们弹性屈曲，并有非常小的（小于或等于100 pN）在空气中的云母表面上的非特异性粘附。对金纳米颗粒标准品上记录的图像的分析表明，这些多壁和单壁碳纳米管尖端分别具有3-6和2-4 nm的曲率半径。此外，从纳米颗粒图像确定的纳米管尖端半径与通过纳米管末端的透射电子显微镜成像直接确定的那些一致。这些分子级CVD纳米管探针已被用于以高分辨率对分离的IgG和GroES蛋白质进行成像。
Carbon nanotubes are potentially ideal atomic force microscopy probes because they can have diameters as small as one nanometer, have robust mechanical properties, and can be specifically functionalized with chemical and biological probes at the tip ends. This communication describes methods for the direct growth of carbon nanotube tips by chemical vapor deposition (CVD) using ethylene and iron catalysts deposited on commercial silicon-cantilever-tip assemblies. Scanning electron microscopy and transmission electron microscopy measurements demonstrate that multiwalled nanotube and single-walled nanotube tips can be grown by predictable variations in the CVD growth conditions. Force-displacement measurements made on the tips show that they buckle elastically and have very small (less than or equal to 100 pN) nonspecific adhesion on mica surfaces in air. Analysis of images recorded on gold nanoparticle standards shows that these multi- and single-walled carbon nanotube tips have radii of curvature of 3-6 and 2-4 nm, respectively. Moreover, the nanotube tip radii determined from the nanoparticle images are consistent with those determined directly by transmission electron microscopy imaging of the nanotube ends. These molecular-scale CVD nanotube probes have been used to image isolated IgG and GroES proteins at high-resolution.