| Summary: | 碩士 === 國立交通大學 === 電子物理系所 === 96 === We present an experimental study for geometric and electronic properties of Au nanoparticles grown on HOPG and Au(111) substrates by scanning tunneling microscope in a ultra-high vacuum. The nanoparticles were fabricated by using inert-gas condensation method. We obtained current voltage (I-V) behaviors of a single Au nanoparticle as a function of the particle size and temperatures. The I-V curves showed Coulomb blockade behaviors and they were fitted with the double-tunneling-junction model. The equivalent capacitances and resistances can be estimated through fitting.
Comparing the I-V curves of Au nanoparticles at room temperature and at 77 K, we concluded that high-temperature I-V behaviors are close to that of Au bulk. In addition, we found that the I-V curves of large Au nanoparticles were close to that of Au bulk as well. We investigated the electronic spectrum of Au nanoparticles on different substrates and at temperatures. We believe that the tunneling spectrum come from both the Au nanoparticles and the substrate. Moreover, we discovered discrete density of states, which were proposed in Kubo theory, in Au nanoparticles.
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