Research On The Individual Carbon Nanotube:Manipulation,physical Properties,and Device Applications

As a quasi-one-dimensional material,carbon nanotube(CNT)has unique properties and wide applications.The investigation of the individual CNT and the understanding of the pristine properties of CNT are crucial for studying low dimensional physics as well as exploring novel devices.In the research on the individual CNT,the realization of the devices has always been a key hurdle.Easily,flexibly and quickly assemble of CNT with the devices is still a big challenge.Here we develop a novel manipulation technique that allows us to operate each CNT under an ordinary optical microscope.A individual CNT can be transferred to the AFM tip,besides,a CNT motor can be realized easily.Based on our directly deterministic assembly of CNT,the novel devices are designed and realized,which combine the TEM grids for determining the chirality with the electrical,optical or thermal measurement of an individual CNT.We study the electronphonon relaxation of the CNT excited by laser pulse.The inferred dark exciton and phonon sidebands were observed except for the bright exciton peaks.And the nonequilibrium phonon was shown by the relaxation of the CNT resistance.We measured the thermal conductivity and thermoelectric coefficient,which are as high as 6000 W/8)?K and 620uV/K in 10um-long CNT at 350 K.Additionally,it`s found that the individual CNT is very sensitive to the electrostatic.We developed a series of applications,such as electrometer,electrostatic probe and scanning electrostatic potential microscopy.Which have some advantages,fast transient response,high sensitivity and nondestructive measurement.Another application is about touch panel,it can provide a sensitive detection of the hover distance,and realize the “hovering” and “touching” control simultaneously and independently.It expands the way of human-computer interaction,and is totally compatible with the flexible electronics.We apply CNT to the nanomechanical resonators,studying the different types of coupling effects.Strong mode-coupling in a CNT resonator was realized by parametric excited,where the strength of coupling is 2-3 orders of magnitude higher than other mechanical resonator system.Based on this,We demonstrated the Rabi oscillation of the coherent phonon between the coupling modes,where the cooperativity coefficient reaches ~250000.Moreover,the strong coupling between two CNT resonators was exhibited,it is the first time that realizing the nonlocal coupling of phonon in nanomechanical resonators.Further,we realized the GHz-CNT mechanical resonators.Owing to the unique selfaligned structure and preloading internal tension in the CNT,the performances are improved in a comprehensive way.Single mode,high frequency,2-3GHz,high quality factor,30000,high tunability,80-110MHz/V,which is 2-3 times larger than the record in CNT.Theoretical analysis indicates that the initial tension can increase the frequency as well as tunability.The largest tunability can be reached by the proper preloaded tension.Our CNT resonator is promising for ground-state cooling and quantum manipulation,as well as the RF applications.In conclusion,the individual CNT was studied in this thesis in three aspects,from manipulation,and its physical properties,then the application of CNT to the nanomechanical resonators.Some progress has been made,and promoting the research on the fundamental properties and practical application of CNTs.