标题: 探索不同尺寸下金奈米颗粒的传输性质
Electrical properties of Au NPs with different sizes
作者: 张逸舜
Chang, Yi-Shuen
简纹滨
Jian, Wen-Bin
电子物理系所
关键字: 金奈米颗粒;Au NPs
公开日期: 2013
摘要: 在本实验中使用两种不同颗粒大小的金颗粒分别为10 nm以及20 nm,而电极间距为200 nm - 600 nm,此实验分为两个部分探讨,第一部分为探讨金奈米颗粒的传输性质,我们量测温度在300 - 30 K内电阻的变化,发现10 nm的电阻随温度下降而上升,20 nm的电阻约在250 K及190 K会有转折点,分析在180 - 65 K时传输机制为最近邻近跳越(nearest neighbor hopping),而65 – 30 K为ES hopping,并由Monte Carlo拟合出的结果可得知两种颗粒大小活化能、穿隧电导的相对关系。
第二部分为探讨金颗粒在照光下会有甚么反应,我们分别比较两种颗粒大小的上升时间(rising time)、光电导。并量测雷射光瓦数改变与电流的关系,由此关系可以由power law得到两种颗粒大小皆为好的感光材料,也发现光电流大小与电极间距有关。
Two different sizes of gold particles are used in this experiment. The average sizes are 10 and 20 nm. The gap of electrode was about 200 to 600 nm for all our devices. This experiment was divided into two parts which will be separately discussed in the following paragraph.
In the first part, we discussed the electrical property of Au nanoparticles. We measure the temperature dependence of resistance at temperatures between 300 K and 30 K. We find out that the resistance of 10-nm-diameter device increases with a decrease of temperature. On the other hand, we observed two transitions at 190 and 250 K in 20-nm-diameter Au particle devices. The electron transport is described well by nearest neighbor hopping in the temperature range from 65 K to 180 K. In addition, it behaves as ES hopping transport at temperatures between 30 K and 65 K. The activation energy and tunneling conductance have been estimated through the Monte-Carlo nonlinear least square fitting.
In the second part, we discussed the photoconductivity of Au nanoparticle assembled arrays. We compared the rising time and photoconductance between two different sizes of Au NPs and measured photocurrent under different power of laser excitation. By fitting the data with power law, we can find that Au nanoparticles are sensitive to light. The magnitude of photocurrent is dependent on the gap length between electrodes.
URI: http://140.113.39.130/cdrfb3/record/nctu/#GT070152062
http://hdl.handle.net/11536/75065
显示于类别:Thesis