化學氣相沉積法製程之多層石墨烯薄膜的兆赫輻射時析頻譜研究

Abstract

石墨烯為碳原子由sp2混成軌域所形成的六角晶格單層薄膜，由於其特殊的能帶結構，而有許多耐人尋味的電子特性。在本文的實驗中，利用化學氣相沉積法在銅箔上成長出單層石墨烯薄膜，透過轉移至藍寶石基板上。進而利用兆赫時間解析頻譜來研究其在此頻段下的電磁特性。利用量測結果與理論分析可獲得溫度與頻率相關之薄膜材料之複數折射率，並進一步求得材料之介電係數、光學電導率，再透過Drude-Model來進行數學擬合，可以得到粒子的散射率。本文將對於所觀察到不同層數對於THz頻段下的響應不同進行討論。

Graphene is composed of a single-atom-thick layer of carbon atoms arranged in a two dimensional honey comb lattice. The unique electronic structure of grapheme gives rise to some interesting phenomenon. In this work, the multi-layers Graphene were deposited on Sapphire substrates by CVD processing. The electrodynamics properties is probed by THz time-domain Spectroscopy. The THz electric fields transmitted through the multi-layer Graphene at room temperatures were measured. The frequency dependence of the complex index of refraction, dielectric function and conductivity can be determined from the complex transmittance and Fresnel equation. In addition, we carefully analyzed the data of conductivity spectra of multilayer Graphene by a simple Drude model including the scattering rate as parameters.