Fabrication Of AFM Carbon Nanotube Probe And Its Metrology Properties Study

Atomic force microscope (AFM) plays a key role in the development of nanotechnology and provides a powerful method for studying the materials topography and micro-interaction between samples. However, the shape and physical characteristics of ordinary AFM probe limit AFM's application. Carbon nanotube (CNT) is considered as ideal AFM probe for its multiple excellent characteristics. In order to combine the advantages of the precision instrument of AFM and the"super fiber"of carbon nanotube, we put forward the subject study of"fabrication of AFM carbon nanotube probe and its metrology properties study". This study provides a simple and reliable approach for fabrication of AFM nantoube probe and other micro/nanodevices, put forwards the specification and evaluation criteria for multiwalled carbon nanotube probe, deeply studies the micro interactions of probe with sample during CNT probe's working, and it shows great significance in study carbon nanotube AFM probe's fabrication and metrology and its other applications.The thesis gives new methods for fabrication of CNT probe on the basis of comprehensive evaluation and analysis of the present status of CNT probe study. Carbon nanotube probes are fabricated by resistance welding and improved arc welding methods under direct view of optical microscopy, and the fabrication mechanism is analyzed. The long carbon nanotube probes are shortened to appropriate length by external voltage and electron bombard methods. It can be lengthened as well by attaching new nanotube using resistance welding method.The image artefacts of CNT probe are generated by approach-bend- adhesion-raise of CNT by the height, phase and amplitude data of artefacts got by CNT probe. The influencing factors of CNT probe artefacts include ratchet effect, probe-sample angle and spring constant of CNT probe. The image artefacts can be reduced by changing the probe scan direction by using ratchet effect. However, increasing the CNT probe spring constant is essential method to eliminate image artefacts.The influences of long-range forces and capillary forces to CNT probe and Si probe are studied by the changes of probe quality constant and resonance frequency and phase theory. The AFM imaging experiments are done to validate the difference of long-range forces and capillary forces'influence to the two kinds of probes. In addition, the interactions of repulsive forces and attractive forces between probes and samples would produce extremum in amplitude vs probe-sample separation curve and result in unstable phenomenon.The specification and evaluation criteria for multiwalled carbon nanotube probe are established, including the lateral spring constant, tip's size and configuration, probe angle and bonding force of multiwalled nanotube probe. The lateral spring constant of multiwalled nanotube probe larger than 0.2N/m and the probe angle smaller than 30 degree are the preconditions for multiwalled nanotube probe stable working. The resolution of CNT probe with hemisphere end is better than the probe with open ended. The bonding strength of carbon nanotube probe is calculated by drawing the ordinary AFM probe and measuring the ordinary probe's deflections. The average bonding force and bonding strength for the CNT probe fabricated by welding method is 2.4 micro newton and more than 3.06×108N/m~2, respectively.