Fast and Simple Methods to Fabricate Graphene/Single wall Carbon Nanotubes Hybrid Structures for Photodetector and Field Effect Transistor Applications

Autor: 李冠廷
Rok vydání: 2018
Druh dokumentu: 學位論文 ; thesis
Popis: 106
We propose two simple and fast methods to deposit single-wall carbon nanotubes (SWNTs) onto interwoven Ni wires, including spraying and electrochemical approaches. Subsequently, graphene-SWNTs hybrid structures were fabricated through a thermal annealing method at a low vacuum condition. The hybrid structures were characterized by field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, Raman spectroscopy, and electrical measurements. The hybrid structure prepared by spraying approach was used as photodetecting arrays with high photoresponse upon laser illumination wavelengths of 976 and 808 nm. The current was nonlinear versus applied voltage (I-V curve), implying the presence of SWNTs between the junctions of vertical and horizontal graphene-SWNTs tubes. The hybrid structure produced high photoresponse for the photodetectors, of which I-V curves are linear or non-linear, indicating that the photocurrent was produced by SWNTs on the surface of graphene tubes. Besides, the electrochemical deposition method was applied to deposit more SWNTs into junctions of Ni wires, following by the formation of the Ni-graphene-SWNTs-graphene-Ni structure at each node after the annealing process. The structure was used as field effect transistors. If silver paste contact the SECNTs, we found that the drain current versus gate voltage (Id-Vg), and the drain current versus drain voltage (Id-Vd) curves showed the characteristics of p-type transistors, which was match with the p-type property of SWCNTs/metal. If silver paste don’t contact the SECNTs, we found that the drain current versus gate voltage (Id-Vg), and the drain current versus drain voltage (Id-Vd) curves showed the characteristics of ambipolar transistors, which was match with the ambipolar property of SWCNTs.
Databáze: Networked Digital Library of Theses & Dissertations
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