Research On The Comparison Of Electronic Properties Between Fullerence And Graphene Devices

The fullerenes and graphene attract many scholars’attentions owe to its’excellent physical andchemical properties. The structure and properties of fullerenes and graphene are expected to bringabout a breakthrough in energy and composite material and transistor and micro-nano electronicdevice and so on. Presently, the relative research and development about fullerenes and grapheneattract the most attention in the world. With the improvement of information, the people’s demand ismore and more about the size of electronic device, the efficacy of processing information and powerdissipation, but the traditional silicon devices have basically approached a limit in these respects. So,it is quite necessary to study the fullerene and graphene device.When the scale of electronic components becoming smaller and smaller, the foregoneelectronics theory is not applicable, so, there is the new theory and nano device. In this chapter, wehave studied the structure and vibration spectrum of C₇₄molecule、the electronic structure andtransmission properties of C₇₄molecular bridge and graphene bridge by using density functionaltheory and nonequilibrium Green’s function and elastic transport theory. Finally, we compare theelectronic transmission properties, and the result shows that the electronic transmission propertiesof C₇₄molecule bridge is better than the graphene bridge. The content as follows:In chapter Ⅰ, this chapter mainly presents the structure、basically physical properties、manufacture method、application area、underlying value of fullerenes and graphene.In chapter Ⅱ, this chapter introduces the density functional theory、nonequilibrium Green’sfunction、elastic transport theory and the relative software.In chapter Ⅲ, Molecular orbital density、vibration spectrum and density of states of fullereneC₇₄molecule are theoretical researched. The result shows that energy gap of C₇₄molecule is nomore than0.6eV. It discovers that the electron which the electronic cloud distributes the HOMOand LUMO state of C₇₄molecule is only distributed the surface of hemisphere of C₇₄molecule, andelectrons show the better distinct character in bonding process. Infrared and Raman spectra of C₇₄molecule show that Carbon-carbon bond vibration is a only infrared active at some points, andRaman active at the others, or infrared and Raman active in some frequency areas. Else, whenconsidering the electron spin, the number of maximums with density of states of C₇₄molecule isincrease and the degenerate energy levels is splited,In chapter Ⅳ, Density functional theory and Tight-binding of nonequilibrium Green’s functionare used to study the molecular orbital, the electronic transmission probabilities and theconductance of fullerene C₇₄.We obtain the orbital energy levels, the transport spectrum, thedensities of states, the I-V curve and the conductance curve of C₇₄ molecule, and explain the electronic transmission probabilities of C₇₄ molecule. The result shows that the C₇₄ molecule hasan excellent electric conduction property.In chapter Ⅴ, Studying the electronic transmission properties and electronic tunnel effectabout face-electrode and line-electrode of C₇₄molecule, the result shows the electron can be able tocross the potential barrier over its kinetic energy and electro nic tunnel effect will disappear whenthe potential barrier is over the certain value in the quantum scale. we study the electronictransmission properties of graphene and find the graphene energy gap is small. The electronictransmission of graphene has distinct switching characteristic. It is likely to happen for electronictunnel effect at-0.9eV～-0.6eV、1.5eV～2.0eV. Finally, comparing the energy spectrum of C₇₄and graphene molecule bridge and the electronic transmission properties.In chapter Ⅵ, we summary the contents of the thesis and put forward for the future work.