研究金奈米粒子石墨烯與電漿子波導於兆赫波段的表面電漿極化子共振現象

Abstract

本論文使用半導體製程於矽晶圓基板上製備金屬光柵奈米結構，並結合 摻雜金奈米粒子之單層石墨烯後完成電漿波導。石墨烯具有優異的載子遷 移率，此特性配合光柵奈米結構，可以由特定之頻率激發產生表面電漿共 振現象。摻雜金奈米粒子可用來改變石墨烯的費米能量，因而可以改變兆 赫波穿透強度與表面電漿共振頻率，進而觀察到共振頻率隨金奈米粒子濃 度變濃而藍移的現象。在理論方面，藉由求解馬克斯威爾方程式與邊界條 件，可以得到共振頻率隨電漿波導費米能量變化之關係，最後以兆赫幅射 時析光譜測量，確認實驗量測之結果與理論預測結果大致吻合。

In this thesis, we investigate the surface plasmon resonance of graphene with gold nanoparticles (Au-NPs) by terahertz time-domain spectroscopy. Graphene has a great mobility in the terahertz spectral region. This property makes graphene a perfect material for the study of surface plasmon resonance. Adding Au-NPs on graphene can change graphene Fermi energy so the transmission and surface plasmon resonance frequency might be changed. We can observe the blue shifts of resonance frequency by enhancing the Au-NPs concentration. First, we prepare a nanostructure consisting of metallic slit grating on the silicon substrate by using semiconductor manufacturing Technology. Then, we transfer graphene with Au-NPs to the grating structure to build the graphene plasmon waveguide. We can get the relationship between Fermi energy and resonance frequency by solving Maxwell equations with appropriate boundary conditions. Finally, we compare the result of experiment measured by THz time-domain spectroscopy with theory. We find that the experiment measurement is in fairly good agreement with the theoretical prediction.