| Summary: | 碩士 === 國立交通大學 === 電子研究所 === 107 === In view of the electrical property research of the diamond nanowires synthesized via pH-induced self-assembly, which we have completed earlier. At this time, we want to evaluate the performance in electrical property and the electron transport mechanism by means of the introduction of metal ions into the self-assembly of diamond nanoparticles for the construction of novel diamond nanowires.
In this thesis, Cd2+ doped hybrid graphite-diamond nanowires (NDS1 NWs) have been successfully grown by means of wet chemical based self-assembly directed DNWs synthesis via the introduction of the Cd2+ on the S1 functionalized nanodiamonds (NDS1). Ultimately, structurally uniform, high aspect ratio and reproducible Cd2+ doped diamond nanowires (NDS1 NWs) have been acquired. The morphology of nanowires have been visualized by SEM and TEM. The self-assembly formation has been confirmed by AFM and TEM. Notably, Raman, XRD and XPS suggest that there might be graphite sheath above the surface of the nanodiamonds (NDS1). According to HR-TEM, we prove that there are certainly the amorphous graphite and the Cd2+ impurity channels wrapping on the surface of the NDS1 NWs.
For the discussion of the variation of conductivities in different nanowires, we successfully fabricate three single Cd2+ NDS1 NW electrical property measurement devices with four, six and ten contacts respectively. The better conductivity of Cd2+ NDS1 NWs we obtain by 4-point probes measurement is 4.70×10-4 (S/cm). The temperature dependence of the Cd2+ NDS1 NWs in the higher temperature range from 300 to 200 K can be explained by thermal activated band conduction, whereas in the lower temperature range from 200 to 80 K can be interpreted as Mott’s 3D variable range hopping conduction. In addition, the conductivity of the Cd2+ NDS1 NWs can not be modulated by the gate bias, partially due to the bad quality of the interface or low carrier concentration in Cd2+ NDS1 NWs.
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