以磁偶極共振耦合效應大幅增益銅箔上石墨烯之準確拉曼訊號

Magnetic Dipole Resonance and Coupling Effects Directly Enhance the Raman Signals of As-grown Graphene on Copper Foil by Over a Hundredfold

陳宗奕 ； 曾奕鈞 ； 林子堯 ； 李仰淳 ； 顧哲揆 ； 陳俊維 ； 陳學禮

《國家奈米元件實驗室奈米通訊》 25卷3期 (2018/09) Pp. 2-8

摘要

大面積石墨烯常以化學氣相沉積法(CVD)製備；原位且非破壞性的檢測方法是重要的。在此，我們示範一種實用方法利用磁偶極共振耦合效應，透過此法，銅箔上石墨烯之拉曼訊號可被直接、準確、大幅增益。矽奈米粒子上之磁偶極共振可被有效耦合至銅箔而引發位於石墨烯及矽奈米粒子間的巨大電磁場。此耦合電磁場可導致石墨烯間的高電磁場熱點(E^2/E_0^2 = 123.2)。即使當我們只放置少許矽奈米粒子於銅箔上石墨烯，可以獲得增益拉曼訊號（約206倍）遠遠大於石墨烯轉置於300奈米二氧化矽膜上（約12倍）。從一連串實驗中比較放置和移除石墨烯上矽奈米粒子之拉曼訊號，我們發現鍍上矽奈米粒子對石墨烯之品質幾乎不會有任何影響。因此，這種基於磁偶極共振耦合效應的方法在石墨烯之原位及非破壞性檢測中是非常有用的，並且不需經過轉置或是有害的製程條件。

關鍵字

拉曼訊號增益 ； 石墨烯 ； 磁偶極共振 ； 耦合效應 ； 非破壞性

並列摘要

Large-area graphene is commonly prepared through chemical vapor deposition (CVD); in situ and non-destructive methods for its characterization are desirable. In this paper, we demonstrate a practical method-exploiting magnetic dipole resonance and coupling effects-with which the Raman signals of graphene on copper (Cu) foil can be directly, faithfully, and greatly enhanced. The magnetic dipole resonance of a silicon nanoparticle (SiNP) can effectively couple its electromagnetic field with the Cu foil to induce an enormous electric field located solely at the position of the SiNP on the graphene. The coupled electromagnetic field can lead to hot spots of high electric field intensity (E^2/E0^2 = 123.2) within the graphene. Even when we positioned only a few SiNPs upon the graphene/Cu foil, we obtained a Raman signal enhancement (ca. 206 times) much greater than that of graphene transferred onto a 300-nm oxide film (ca. 12 times). From a series of experiments comparing the Raman signals of graphene before and after removing the SiNPs on the graphene/Cu foil, we found that the coated SiNPs had almost no effect on the quality of the as-grown graphene. Thus, this approach based on magnetic dipole resonance and coupling appears to be very useful for in situ and non-destructive characterization of as-grown graphene on Cu foil, without the need for transfer processes or harmful processing conditions.

並列關鍵字

Raman Signal Enhancement ； Graphene ； Magnetic Dipole Resonance ； Coupling Effect ； Non-destructive