過渡金屬二硫族化物(Transition-metal dichalcogenides, TMDs)，是由過渡金屬元素與硫族元素所構成，以及單層二維材料可以穩定存在自然界中，再加上元素組合不同而有眾多材料特性(絕緣體、半導體、導體等)，是近年來矚目的材料之一。本論文進行WSe2與NbSe2的研究，一開始著重材料的成長部分，從設備的架設到長出單層整面WSe2，與直徑2吋大面積的WSe2，可證明LPCVD系統成長WSe2的方式是能夠量產大面積材料。另一方面我們透過硒化氧化物的方法，去進行WSe2的Nb摻雜，希望提高材料的應用價值。
元件部分在單層整面WSe2元件的電流最高可達十幾nA/µm，電流開關比可到10^4到10^6，最好的次臨界擺幅有96 mV/dec，相當適合往邏輯電路去作發展，並確定成長於氧化鋁基板的WSe2為P型半導體的材料。另外在硒化氧化物所製成的元件部分，在材料WSe2中有Nb的摻雜，微量摻雜Nb 5%的況，電流與載子濃度最大，電流開關比只有 1.1，而次臨界擺幅的部分為12.77 V/dec，呈現金屬特性。透過不同混合比例，我們提出較佳的摻雜範圍在Nb 0-5%。

Transition-metal dichalcogenides is constituted by transition metal and chalcogenide elements. The two dimensional monolayer material is able to be stable in nature. Depending on the selection of the metal, these materials may exhibit insulator, semiconducting, or metallic properties. It attracts much attention in recent years.

This thesis discusses the growth of WSe2 and NbSe2. Initially, we construct the equipment (i.e. furnace) by self. We will then describe WSe2 monolayer and large-scale of WSe2 which is 5 centimeters in diameter. It proves the LPCVD could deposit large-scale WSe2. On the other hand, we use selenization of transition metal oxide to form Nb-doped WSe2. We hope to upgrade the value in this application.

In devices, the maximum current of monolayer WSe2 reaches 12 nA/µm and on/off current ratio is 10^4 to 10^6. the best subthreshold swing is up to 96 mV/dec. It is very suitable for logic circuit design. On the other hand , the doping concentration of Nb-doped WSe2 is below 5%. The current and mobility are larger. It only exhibits an on/off current ratio of 1.1 and subthreshold swing of 12.77 V/dec. It appears to be metallic.

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