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Studies On Anomalous Hall Effect Of Graphene And Magnetic Field Control Of Hysteresis Characteristics In Carbon Nanotube Field Effect Transistors

Posted on:2021-03-08Degree:MasterType:Thesis
Country:ChinaCandidate:Z S PengFull Text:PDF
GTID:2381330602466212Subject:Microelectronics and Solid State Electronics
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Graphene and carbon nanotubes have many excellent physical properties and are ideal materials for nanodevices.With the development of carbon-based magnetism,graphene and carbon nanotubes have become important research objects for new-generation electronic devices.Graphene and carbon nanotubes have excellent characteristics in spin transport,the spin diffusion length can reach the order of micrometers,so they have high research value in carbon-based magnetism and their devices.This thesis is mainly the research of the physical properties in graphene and carbon nanotube electronic devices,especially the physical phenomena related to carbon-based magnetism.First,we construct a monolayer graphene-based Hall device and explore its anomalous Hall effect.Second,we study the hysteresis characteristics of single-walled carbon nanotube field effect transistors and found that it can be controlled by magnetic fields.There are two main topics in this thesis,as listed below:Firstly,we construct a monolayer graphene Hall device and observe the anomalous Hall effect in the graphene Hall bar device.Without an external magnetic field,the Hall resistance(Rxy)was measured in the graphene Hall device,and the Hall resistance increased as the graphene disorder increased.Comparing the Raman spectra of graphene in the device before and after heat treatment,the intensity of the D peak is enhanced and the ID/IG is increased from 0.31 to 0.58.At the same time,after heat treatment of the device,the Hall resistance Rxy of the device changed from 0.3 k?before heat treatment to 6.9 k?,which indicates that the abnormal Hall effect of single-layer graphene is induced by defects in the graphene Hall bar of the device.The Hall resistance of the device can be adjusted by the gate voltage,and the maximum can reach11.4 k?,and the Hall angle is about 0.26.In addition,the lateral resistivity?xy is proportional to the longitudinal resistivity?xx,and the experimental results are consistent with the skew scattering mechanism of the anomalous Hall effect.Secondly,we demonstrate a hysteresis characteristic related to magnetism of a single-walled carbon nanotube field effect transistor.The mechanism may be related to the existence of magnetic moment in the single-walled carbon nanotube?SWNT?.Under atmospheric conditions at room temperature,the electrical properties of single-walled carbon nanotube field effect transistors were measured and found that there is an obvious electrical hysteresis in the device.This hysteresis characteristic can be controlled by an external magnetic field,and there are large differences in the hysteresis characteristics of the device under positive and negative magnetic fields,which may be related to the magnetic anisotropy of single-walled carbon nanotubes.Therefore,such single-walled carbon nanotube transistors have great potential in spintronic devices,providing a new method for the development of non-traditional integrated circuits with high density and low power consumption.
Keywords/Search Tags:monolayergraphene, anomalous Hall effect, single-walled carbon nanotube field effect transistor, electrical hysteresis, magnetic moment
PDF Full Text Request
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