Effects of cross-sectional area on the tunneling-junction array in octahedral PbSe colloidal-nanocrystal solids
Shao-Chien Chiu1, Jia-Sin Jhang, Jenn-Fang Chen
1Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan. wbjian@mail.nctu.edu.tw.
Abstract:
Octahedral PbSe colloidal nanocrystals (NCs) are used to assemble a solid. Because of the special feature of the apexes of the octahedrons, the cross-sectional area of the inter-dot tunneling junctions is much smaller than that formed between spherical NCs. The inter-dot separation between NCs is easily adjusted by mild thermal treatment. Like a spherical NC-solid, the resistance of the octahedral NC-solid is exponentially dependent on the inter-dot separation. On the contrary, due to the difference in the cross-sectional area between the NCs, electron transport in the octahedral NC-solid does not follow the same model used for the explanation of electron transport in a spherical NC-solid. Through analyses of current-voltage and resistance-temperature behaviors, we have confirmed that the model of fluctuation-induced tunneling conduction fits very well with all of the data and explains the variation in the electrical properties of octahedral PbSe colloidal NC-solids after thermal annealing.
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