二維材料，像是石墨烯和過渡金屬硫屬化合物已成為現今電子和光電應用中的重要趨勢。石墨烯是目前宇宙中已知最薄和高機械強度的物質。它具有高電子遷移率，零有效質量，高透光率和高電導率等許多優良的特性。石墨烯會吸收大氣中的氧原子和水氣呈現 p型的性質。二硫化鉬是過渡金屬硫屬化合物中的材料，呈現 n型的半導體材料特性。它具有高光響應度，高的載子遷移率和高電導率等特性。在本實驗中，我們透過化學氣相傳導法成長二硫化鉬單晶塊材。用甲烷作為碳源以化學氣相沉積法在銅箔基板上成長石墨烯。透過量測掃描式電子顯微鏡，X射線能量散佈光譜分析儀和拉曼光譜儀來分析二硫化鉬和石墨烯的基本特性。透過電荷中性點量測來判斷二硫化鉬和石墨烯的半導體特性。在p-n接面電晶體的應用上，我們將二硫化鉬塊材和石墨烯薄膜堆疊合成p-n接面電晶體。在-4 到 +4 V偏壓下量測p-n接面電晶體 I-V特性曲線，並量測其半波整流。結果表明，在輸入電壓為2 V，頻率為100 Hz的訊號下，整流性能可以很好地顯示出來。另一方面，我們成功設計並製作出垂直堆疊的雙極性接面電晶體，並用不同接觸電極進行嘗試，通過比較，量測共射極直流電流放大係數β值最大的值約為2.7。

Two-dimensional materials, such as graphene and transition-metal dichalcogenides (TMDs) have recently become an important trend in electronic and photoelectric applications. Graphene is the thinnest known material in the universe and the strongest ever measured. It is a wonder material with many superior characteristics, such as high electron mobility, zero effective mass, high light transmittance and high electrical conductivity. The synthesized graphene exhibits p-type behaviors because of oxygen and water vapor in air. Molybdenum disulfide (MoS2) is an n-type semiconductor material of the TMDs. It has high optical responsivity, high carrier mobility, and high electrical conductivity. In this experiment, we used chemical vapor transport method (CVT) to synthesize MoS2 single crystals. Graphene was used CH4 gas as the carbon source to grow onto a copper foil substrate. The basic properties of synthesized MoS2 and graphene were measured by SEM, EDS and Raman spectrometry. Measuring the charge-neutrality point (CNP) to examine the semiconductor properties of MoS2 and graphene. In the application of p-n junction diodes, we combined MoS2 and graphene to produce p-n junction diodes. The I-V characteristics of p-n junction diodes were measured of applied voltage ranged within -4 to +4 V. The results of half-wave rectification experiment were conducted. It showed that the rectifying behavior could be well shown under 100 Hz of applied voltage with 2 V. In addition, we designed and fabricated a compact vertically stacked n-MoS2/p-graphene/n-MoS2 bipolar junction transistor (BJT). The bipolar junction transistor was successfully fabricated, and we used different contact materials as electrode, the maximum common-emitter current gain (β) was about 2.7.

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