隨著資訊科技產業的蓬勃發展，如何縮小電子產品內部的半導體元件並提升運算速度儼然成為最重要的議題之一，除了不斷突破製程微縮化極限，也在尋求能夠取代矽的替代材料。過渡金屬硫化物 (Transition metal dichalcogenides, TMDCs) 在能隙與厚度之間有著相依的關係，加上高載子遷移率和高電流開關比的特性，在電晶體元件和光電元件的應用上具有相當大的潛力。本研究結合化學氣相傳導法 (Chemical vapor transport, CVT) 能夠合成大量高品質TMDCs晶體與機械剝離法 (Mechanical exfoliation) 簡易操作的優點，製備不同元素比例之Mo1-xWxS2 (x=0, 0.1, 0.3, 0.5, 0.7, 0.9, 1) 薄片樣品，利用掃描式電子顯微鏡做表面形貌與厚度分析，確認樣品皆為厚度3-5 m的層狀材料，並以X射線能量散佈能譜儀、X光繞射儀與拉曼光譜儀分析材料的成分組成，確認Mo1-xWxS2系列晶體品質良好且元素比例正確。接著我們透過電荷中性點量測了解晶體的半導體特性，將n-type的MoS2分別與不同元素比例之Mo1-xWxS2薄片樣品疊合，製作出p-n與n-n異質接面二極體，並成功量測其二極體電流-電壓特性曲線以及應用於半波整流電路當中，發現MoS2疊合Mo0.9W0.1S2的p-n異質接面二極體擁有優異的整流特性，整流的工作頻率從1 Hz到1 kHz，工作電壓落在1 V至5 V。

With the vigorous development of the information technology industry, how to reduce the internal semiconductor components of electronic products and increase the computing speed has become one of the most important issues. Not only do the developers spare no effort to break the limits of process miniaturization constantly, but they also keep seeking alternative materials that can replace silicon. Transition metal dichalcogenides (TMDCs) have a dependent relationship between the energy band gap and the thickness. With the characteristics of high carrier mobility and high on-off ratio, they present considerable potentials in transistor and optoelectronic devices. In this study, we use the chemical vapor transport (CVT) method to synthesize plenty of high-quality Mo1-xWxS2 crystals with different proportion (x=0, 0.1, 0.3, 0.5, 0.7, 0.9, 1) and divide the crystals into thin films by the mechanical exfoliation method. To confirm that the samples are all layered materials with a thickness of 3-5 m, we use scanning electron microscope (SEM) to do surface morphology and thickness analysis. Qualitative and quantitative analyses are conducted using an energy dispersive X-Ray spectroscopy (EDS), X-ray diffractometer (XRD) and Raman spectrometer. The results indicate that the composition ratio of is correct. Then we obtain the information of the semiconductor conductivity type of the Mo1-xWxS2 series crystals by measuring the charge neutral point (CNP). Subsequently, the n-type MoS2 is stacked with Mo1-xWxS2 thin film samples with different composition ratios respectively to produce p-n and n-n heterojunction diodes. After the p-n and n-n diode current-voltage characteristic curve is measured successfully, we apply the p-n and n-n heterojunction diodes to the half-wave rectifying circuit. The results suggest that that the p-n heterojunction diode made of MoS2 and Mo0.9W0.1S2 has best rectification characteristics. This p-n diode was applied in the half-wave rectifying circuit at an operating frequency of 1 to 1000 Hz and an operating voltage of 1 to 5V.

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