| dc.description.abstract | Since it was discovered in 1991, carbon nanotube (CNT) has become a rising nano-material because of its unique physical and electrical properties. We can use several kinds of advanced microscopes such as scanning probe microscope (SPM), scanning electron microscope (SEM), and transmission electron microscope (TEM) to observe CNTs. However, these microscopes often have a lot of constraints and they are often labor-demanding. Therefore, it is a very important and practical topic to observe CNTs in a more convenient fashion.
In this article, we try to observe CNTs by using traditional optical microscope (OM), and to locate the position at the same time. Thus we can find out CNTs rapidly by atomic force microscope (AFM), and it is helpful for further measuring and manipulation.
In the process, we find some interesting phenomena: The OM image of CNTs can’t be observed at first, and then appears as time goes, and finally disappears again. We propose that this phenomenon is caused by the liquid film on the surface. Further, we find the relative humidity (RH) will also influence the CNTs’ OM image under the same mechanism.
We try to practice AFM lithography on CNTs / Si to test the effect of H2O film indirectly. At low RH, the oxide stripes look like to be underneath the CNTs. However, at high RH, the stripes look like to stride across the CNTs.
Besides, we made some attempt on CNT manipulation. In a 3-D version, CNTs can be attached on the tungsten tip by dielectrophoresis. In a 2-D version, CNTs can also be moved or cut using an AFM tip. These manipulation methods are expected useful for nano device.
We hope that the discovery and our understanding of these phenomena can be useful for future research on CNTs, and other 1-D nano wire as well. | en_US |