Control of Curvature in Highly Compliant Probe Cantilevers during Carbon Nanotube Growth

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• 作者：I-Chen Chen ; Li-Han Chen ; Christine A. Orme ; Sungho Jin
• 刊名：Nano Letters
• 出版年：2007
• 出版时间：October 2007
• 年：2007
• 卷：7
• 期：10
• 页码：3035 - 3040
• 全文大小：417K
• 年卷期：v.7,no.10(October 2007)
• ISSN：1530-6992

文摘

Direct growth of a sharp carbon nanotube (CNT) probe on a very thin and highly flexible cantilever by plasma-enhanced chemical vapordeposition (PECVD) is desirable for atomic force microscopy (AFM) of nanoscale features on soft or fragile materials. Plasma-induced surfacestresses in such fabrication processes, however, tend to cause serious bending of these cantilevers, which makes the CNT probe unsuitablefor AFM measurements. Here, we report a new tunable CNT growth technique that controls cantilever bending during deposition, therebyenabling the creation of either flat or deliberately curved AFM cantilevers containing a CNT probe. By introducing hydrogen gas to the (acetylene+ ammonia) feed gas during CNT growth and adjusting the ammonia to hydrogen flow ratio, the cantilever surface stress can be altered fromcompressive to tensile stress, and in doing so controlling the degree of cantilever bending. The CNT probes grown under these conditionshave high aspect ratios and are robust. Contact-mode imaging has been demonstrated using these probe tips. Such CNT probes can beuseful for bio-imaging involving DNA and other delicate biological features in a liquid environment.