自單層石墨烯被發現以來，二維材料在研究和發展上，獲得了顯著地關注。其中，具半導體性的過渡金屬二硫屬化物(TMD)，於單層時因其直接能隙、優異的電子遷移率(mobility)及開關電流比(on/off ratio)等物理特性，適用於各類光電元件、感測器等應用，有機會成為下世代之半導體或光電產業的主流材料。隨著元件尺度微小化，材料本質缺陷亦顯著影響其物理性質，因此，材料之微區分析技術逐漸成為關鍵議題。
本研究以不同二維晶體堆疊產生的各類型莫列波紋(Moire ́ pattern)為重點。實驗中成功藉由水轉移技術成功將CVD合成之TMD材料轉移至HOPG基板，進行STM分析，並深入探討材料之晶體結構、缺陷類型及分布；並以理論模型，計算各種材料堆疊及其Moire ́週期與角度的關係。此外，藉由外加偏壓的調控，觀察其相同Moire ́週期下原子影像之變化。

Since graphene was discovered, researches on two-dimensional materials has attracted a great deal of attention. Among them, transition metal dichalcogenides (TMD) semiconductors seem to be candidates for diverse applications of optoelectronic and sensors, due to their unique properties of direct bandgap, high mobility and high on/off ratio. As devices scaling down, properties of materials are significantly affected by intrinsic defects, atomic-resolved analysis thus becomes critical issues.
In this work, Moire ́ pattern resulted from different stacking of two-dimensional TMD materials has been emphasized. Monolayer TMD has been successfully transferred to the substrate (HOPG) by water-mediated transferring technique and analyzed with Scanning Tunneling Microscope (STM), for further characterization of the atomic structures and defects within materials.
Using the model of vector relation in reciprocal space, we combined the theoretical results with experimental results to calculate the relation between the periods acquired from Moire ́ pattern and misorientation angle of vertical-stacked heterostructure.

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