Nanodevices Based On Individual One-Dimensional Nanostructure And The Studies Of Its Properties

In this dissertation,two kinds of typical one-dimensional(1D)nanostructures (1D tellurium nanotubes and 1D silver nanostructures)have been prepared and characterized in detail,respectively.The physical properties of nanodevices based on the individual as-prepared 1D nanostructure have been studied fully.The main results can be briefly described as follows:1.Ultralong and uniform single crystalline Te nanotube-based nanoscale devices have been constructed by using focused ion-beam(FIB)technique.R-T,andâ… -â…¤curves of individual Te nanotube,which was prepared by a surfactant assisted solvothermal approach,have been firstly measured in the temperature range of 5-300 K,indicating metallic character of the as-prepared Te nanotube with a T² dependence of the resistance,which was also consistent with the results by photoconductivity measurement.The results demonstrated that unintentional doping during the chemical preparation process of the Te nanotubes might attribute to the change of electrical structure of the Te nanotubes,which was supported by first-principles density-functional theory calculations.The room temperature resistivity of the individual Te nanotube was found to be 9.854μohm.m,and the ratio of the minimum resistivity at 5 K to that at room temperature was 0.47.The results indicated that the Te nanotubes synthesized by chemical approach could act as interconnects and active components in nanoscale devices and field emission devices.2.Ultralong Ag@C nanocables have been synthesized from a modified hydrothermal carbonization approach.Nanoscale devices based on individual Ag@C nanocable have been constructed by using focused ion-beam(FIB)technique.R-T, andâ… -â…¤curves of individual Ag@C nanocable were measured by using the four-probe method in the temperature range of 5.76-300 K,indicating typical good metal character.The room temperature conductivity of the individual Ag NW core was found to be about 5.96×10⁵ S/cm,almost retaining the excellent properties of the bulk silver.The maximum current density before failure was measured to be 1.3×10⁷ A·cm^-2.The core-sheath structure of Ag@C nanocables exhibits several advantages over naked Ag nanowires,i.e.,the outer isolating amorphous carbon sheath can protect the Ag NW core,keep its stability,and prevent it from being oxidized and eroded;and the Ag NW core retains the excellent properties of the bulk silver.The present study indicated that the Ag@C core-sheath nanocables could act as a kind of ideal nanobuilding blocks for interconnects in future.Furthermore,similar core-sheath nanostructures,such as copper,and aluminum,could be also prepared, which are cheaper and have been broadly applied in commercial ways.The conducting performance and stability of these metal nanowires could be potentially enhanced by processing these metals into core-sheath cable-like nanostructures.