CVD Graphene/WSe2/Graphene transistors: influence of graphene contacts

二維材料的發現引起許多人的關注，隨著科技的發展，元件尺寸越做越薄，元件的製作也面臨許多挑戰，二維材料與金屬的接觸產生過大的接點電阻，接點電阻會影響電晶體本身的特性使它元件特性變得很差，因此許多人研究橫向石墨烯與二硫化鉬或是石墨烯與二硫化鎢異質結構的接點電阻，證實石墨烯確實能夠降低接點電阻，然而許多人的文獻資料都在研究n型半導體材料，缺乏p型材料是否也適用於此結果。在這裡使用CVD成長石墨烯與二硒化鎢製成異質結構電晶體，並透過直流量測與低頻雜訊量測結果，皆證實石墨烯能夠降低接點電阻(Rsd)使得Graphene/WSe2/Graphene電晶體的Ion/Ioff大於106與各項參數皆有提升，並透過低頻雜訊量測分析載子傳輸機制為載子數擾動(CNF)，是因為載子被缺陷捕捉與釋放所引起，缺陷不僅僅來自於介電層表面與通道表面，更包含了通道內的載子缺陷密度，通道內的載子缺陷密度透過分析明顯多於介電層與通道表面的影響，為了實現場效電晶體的應用我們透過示波器量測開關速度與透過外接電路實現邏輯反相器的應用The discovery of two-dimensional materials has attracted many people's attention, with the development of science and technology, the more thin the component size, the production of components has also face many challenges. The two-dimensional material and metal contact to produce contact resistance, contact resistance will affect the characteristics of the transistor itself so that its component characteristics become very poor. As a result, many people study the contact resistance of transverse graphene and molybdenum disulfide or graphene to the heterogeneous structure of tungsten disulfide. It is confirmed that graphene can actually reduce contact resistance, but many people's literature is studying n-type semiconductor materials, and the lack of p-type materials also applies to this result. The use of CVD grown graphene and WSe2 as a heterostructure transistor, and measured by direct flow measurements and low-frequency noise measurements, have confirmed that graphene reduces contact resistance (Rsd) and makes Graphene/WSe2/graphene transistors Ion/Ioff is greater than 106 and all parameters are elevated. The carrier number fluctuation (CNF) is analyzed by the low frequency noise, because the carrier is caused by the defect catching and releasing. The defect not only comes from the surface of the dielectric layer and the channel surface, but also contains the density of the carrier defect in the channel. In order to realize the application of field-effect transistor, we measure the switching speed of two kinds of components through an oscilloscope and realize the application of logic inverter through the external circuit.中文摘要 i Abstract ii 圖目錄 v 第一章 緒論 1 第二章 文獻回顧 2 2-1 二硒化鎢元件特性 2 2-2 二維材料接點電阻 7 2-3 研究動機 12 第三章 原理 13 3-1 場效應電晶體 13 3-2 低頻雜訊 17 第四章 實驗 23 4-1 元件 23 4-2 實驗設備 24 第五章 結果與討論 26 5-1 元件結構及材料特性 26 5-2 基本電學特性 27 5-3 低頻雜訊分析 30 5-4 應用 36 第六章 結論 38 參考資料 4