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Piezoelectric Potential Distribution in Bent Zinc Oxide Nanowire
Posted 7 giu 2012, 05:16 GMT-4 MEMS & Nanotechnology, MEMS & Piezoelectric Devices Version 4.2 5 Replies
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I did a simulation about the piezoelectric potential distribution in a bent zinc oxide nanowire reported in a previous literature. But my result is weird, it doesn't consistent with the literature's result. In my simulation the piezoelectric potential exists only in the bottom of the nanowire, but in the literature the piezoelectric potential also exists in the rest part of that wire. I am very confused and couldn't find the reason for this discrepancy. Can anyone help me with this problem?
In my attachment is the mph file and that literature.
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if you plot the stress tensor of your beam you will see that the stress is mainly at the attachment of your wire, this is consistent with what one should expect.
However if you plot log(V) instead of V you will notice that you have voltage all along but it droops very rapidly when you move away from the fixed I/F
Now the results are very different I agree, so I suspect that your PZT orientation is not coherent with the one of the paper.
And check the doc for the tensor convention used. COMSOL uses the IEEE convention for PZT tensor definitions, which is different w.r.t. index use of the classical one used for anisotropic structural, and perhaps different from the one used in the article.
Furthermore, you might need to define a user coordinate and use that to define your true PZT orientation
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Good luck
Ivar
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Thanks for you sincerely advice. The literature also used the Voigt notation as is in the comsol doc. I have modified the material's properties and made them consistent with the literature. In addition I have defined a user coordinate and use that to define my true ZnO orientation. But the result are still quite different. Besides the nearly localized behavior of the calculated piezoelectric potential, its magnitude is ten bigger than the literature. Is there some vital mistake in my model? Thanks for your response!
The attachment is my modify mph file and a doc of my input parameter.
Attachments:
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have you tried to flop your base vector orientation exchanging X nad Z or rotating it around ?
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Good luck
Ivar
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I have rotated my local coordinate about y axis by 90 degrees, and this time its results did change however that result still doesn't consistent with the literature. In addition the actual polar direction is along the wire's axis, if I exchange z and x the polar direction would perpendicular to the wire's axis and this is contradict with its actual situation.
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