Rare SWCNT materials contain both metallic SWCNT （m-SWCNT） and semi-conducting SWCNT（s-SWCNT）. Since m- SWCNT and s-SWCNT have very different applications, it is necessary to differentiate them so as to further separate them for more efficient CNT utilization. To achieve this goal, the authors established a dielectric force microscope （DFM） detection system to differentiate s-SWCNT from m-SWCNT, based on different 2c~ force decided by SWCNT＇s conductivity under AC electric field. The experimental results showed that s-SWCNT can be clearly differentiated from m-SWCNT. The statistics analysis shows that the detected number proportion of s-SWCNT to m-SWCNT matches the well-known proportion 2：1 in the normally prepared CNT materials. The above results strongly verified the effectiveness of the detection system.
At present,study on dynamic tensile properties and atomic chain fabrication of single nanowire,for understanding its dynamic tensile properties and unique physical properties of atomic chain to fabricate atom scale devices,is one of frontier research issues in nanoscale science.However,how to assemble single nanowire on a tensible microstructure becomes one of the most difficult problems,which severely restricts the development of this research field.In this paper,after the ultrahigh tensible microelectrode chip is fabricated by MEMS technology,hexamethyldisilazane is utilized to improve hydrophobicity of the chip,and then a microdroplet dielectrophoresis experimental platform and technology is developed to assemble single nanowire on the sensible microelectrode.Experimental results show that accurate and efficient assembly of single Cu nanowire is realized,which contribute greatly to the further research of dynamic tensile properties and atomic chain fabrication.And for guiding the assembly experiments,finite element technology is also utilized to analyze the local microelectro field around the microelectrodes during dieletrophoresis experiments.
Chaolei HuangHongjiang ZengXiaojun TianJie LiuZaili DongTie LiYuelin Wang
Nowadays,one of the bottlenecks which hinder the development and application of carbon nanotube(CNT)nano device is that no pure semiconducting CNT(s-CNT)or metallic CNT(m-CNT)can be obtained,and for solving this problem scientists proposed some methods on preparation or separation,but all the results still should be detected and feedback to the process for further improving the preparation and separation methods.Thus,it is very important to measure and distinguish the electrical properties of CNT.For that,scientists proposed a method to measure CNT electrical properties based on DC electrostatic force microscope(EFM)mode,which distinguishes m-CNT from s-CNT according to different scan line shape to CNT with different electrical properties.But,we discovered that the probe lift-up height will seriously affect the shape of the scan line,which makes this method not reliable in distinguishing m-CNT from s-CNT.In this paper,the authors deeply researched the influence of probe lift-up height and also gave corresponding theoretical analysis and explanation,which will greatly improve the method of detecting CNT electrical properties by EFM.
Zengxu ZhaoXiaojun TianJie LiuZaili DongLianqing Liu
