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Piezoelectric potential output from ZnO nanowire functionalized with p-type oligomer

Song, Jinhui and Wang, Xudong and Liu, Jin and Liu, Huibiao and Li, Yuliang and Wang, Zhong Lin (2008) Piezoelectric potential output from ZnO nanowire functionalized with p-type oligomer. NANO LETTERS, 8 (1). pp. 203-207.

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Official URL: http://pubs.acs.org/doi/abs/10.1021/nl072440v

Abstract

We have studied the piezoelectric potential output of a ZnO wire/belt functionalized with p-type oligomer (2,5-Bis(octanoxy)-1,4-bis(4-formyl phenylene vinylene) benzene) (OPV2) when it was deflected by an atomic force microscope (AFM) tip in contact mode. In comparison to the ZnO wire/belt without oligomer coating, an extra positive voltage peak was observed prior to the appearance of a negative potential peak. The paired positive and negative voltage peaks are the results of tip contact to the stretched and the compressed side of the wire/belt, corresponding to the positive and negative local piezoelectric potential, respectively. The p-n junction between OPV2 and ZnO serves as a ``diode'' that controls the flow of current. When the nanowire/nanobelt is first bent by the AFM tip, the diode is reversely biased and the piezoelectric charges are stored in the ZnO wire/belt. As the AFM tip further bends the wire/belt, the local piezoelectric potential is continuously accumulated to a value that is large enough to break through the diode. Then the free charges from the external circuit can flow in and neutralize/screen part of the piezoelectric charges, resulting in a positive pulse in the output signal. When the AFM tip continues to scan to reach the compressed side of the ZnO wire/belt, the p-n junction is forwardly biased. Neutralizing/screening the residual and the newly created piezoelectric charges leads to the flow of current from the tip to the ZnO wire/belt, resulting in a negative voltage pulse. This study supports the charging and discharging model proposed for the piezoelectric nanogenerator.

Item Type:Article
Subjects:Physical Science > Nanoelectronics
Engineering > Nanotechnology applications in ICT
ID Code:440
Deposited By:Farnush Anwar
Deposited On:12 Dec 2008 10:35
Last Modified:12 Dec 2008 10:35

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