以穿透式電子顯微鏡分析化學氣相沉積法成長之石墨烯堆疊形式

Abstract

石墨烯是近年來炙手可熱的二維材料，擁有良好的性質之外，更被大量應用在不同的領域中，然而不同層數和不同堆疊型態的石墨烯薄膜有不同的物理化學性質，適合使用的地方也不盡相同，因此判斷石墨烯薄膜的層數和堆疊方式就成為重要研究主題，一般方便且非破壞性的量測工具為拉曼光譜儀，藉由特徵峰的峰值對比可以快速得到石墨烯層數的訊息。在本論文中，藉由實驗室使用化學氣相沉積法成長得到的石墨烯薄膜進行分析發現了拉曼光譜儀與穿透式電子顯微鏡橫截面分析產生不一致的現象，利用掃描式電子顯微鏡、拉曼光譜儀、穿透式電子顯微鏡橫截面影像以及平面視角的穿透式電子顯微鏡繞射分析，證明本實驗室所製備的石墨烯薄膜，與之前文獻觀察得到的堆疊型態有所不同，且層數的判斷也需更多實驗佐證，其分析方法展示了二維奈米薄膜材料仍有許多值得研究的空間。

Graphene is a popular two-dimensional material which owns a lot of great properties, hence, it has been applied in many areas, such as integrated circuits, bio-sensor, solar cell, and so on. Owing to its great versatile application, it is important to determine the number of layers and the stacking form of graphene. With different number of layers and stacking forms, graphene can present variety properties. Usually, Raman spectroscopy is one of the most important and convenient instrument to determine the number of layers of graphene. In the thesis, we found that some inconsistency between the result of Raman spectroscopy and the cross-sectional Transmission Electron Microscope (TEM) images. Therefore, with the chemical-vapor-deposition (CVD) growth graphene, we use scanning electron microscope (SEM), Raman spectroscopy, cross-sectional TEM images and plan-view TEM diffraction intensity analysis to determine the real number of layers and the stacking form of graphene. It turns out that the stacking form of graphene is different from the expected results, and the number of layers of graphene cannot be judged easily by Raman spectroscopy. Further analysis is required to understand the microstructure of this two-dimensional material.