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Effect of an interface charge
density wave on surface plasmon
resonance
in ZnO/Ag/ZnO thin films
教授:林克默博士
學生:董祐成
日期:2010/12/21
Outline
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Introduction
Experimental
Result and Discussion
Conclusion
Introduction
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In this work, we present evidence of resonance
between SPPs and incident light in ZnO films with
embedded Ag.
The mechanism of the optical transmission
enhancement through a ZnO film with embedded Ag
will also be discussed by considering the role of
ICDWs in optical transmittance.
The surface plasmon resonance SPR wavelength was
calculated to explain the redshift that accompanies an
increasing top ZnO layer thickness.
Experimental
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ZnO/Ag/ZnO films were deposited on glass
substrates using a dc magnetron sputtering system
(NACHI, SP-1530–1) at room temperature.
The Ag layer was deposited under argon [50 SCCM
(SCCM denotes cubic centimeter per minute at STP
atmosphere)]. The ZnO layer was deposited under
argon 50 SCCM mixed with oxygen 3 SCCM.
Result and Discussion
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Figure 1 shows the top-view SEM image of Ag
deposited on ZnO. The Ag layer is not smooth but
has a layer-plus-island nanostructure.
The random Ag islands can be thought as a grating
with a random grating constant,α The random grating
widths were distributed from 17.5 to 600 nm.
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Figure 2a shows the change in the bulk electron
concentration of the Ag layer in ZnO/Ag/ZnO films
as a function of the top ZnO layer thickness.
The bulk concentration increased as the top ZnO
layer thickness increased from 5 to 20 nm.
In multilayer films, carriers were transferred to ZnO
after it was placed in direct contact with Ag.
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Figure 2b shows the optical transmittance spectra and
the calculated ICDW of the ZnO/Ag/ZnO films.
The transmittances of the ZnO/Ag/ZnO were higher
than that of a single layer film of ZnO or Ag.
his is a broad transmission enhancement area in the
visible range. The positions of maximum
transmission can be observed as a redshift with
increasing top ZnO layer thickness.
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The PL spectra peak shifted from 3.25 to 3.18 eV.
The PL spectra for metal–ZnO films have been
discussed by Haglund et al.4 in a study of enhanced
optical transmittance.
They showed that the peaks do not shift for a fixed
thickness of the ZnO layer.
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It is clear that the resonance wavelength of the ICDW
shows the same trend with the experimental result,
and their positions of maximum values are
approximate.
Conclusion
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氧化鋅薄膜嵌入銀光穿透的增強進行了研究，光
傳輸是增強是因為SPR還有界面振盪的電子密度
而引起的。
當控制氧化鋅上層的厚度在可見光範圍內最高的
穿透率位置從496.5至541奈米，該最大穿透率的
位置可以被調整。
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