同步輻射X光繞射實驗技術於奈米級別二維結構結晶分析以及應用

Application of synchrotron X-ray diffraction technology for crystal state of nano-scale 2D materials

二維材料因具備優秀的電子及光學性質，可成為新世代之半導體材料而備受期待，然因其單原子層結構之特性，在多種分析，尤其是結晶結構分析時因訊號強度問題導致訊號取得困難重重。同步輻射光源為台灣先進光源設施，可提供高亮度高精度之光源，輔以多種後端實驗站設計，配合研究需求，可提供優良之樣品性質測試平台，其中繞射實驗(TLSBL-17B1)站乃針對磊晶及奈米級結晶結構所設計之先進研究設施，可以針對二維材料提供結構以及對稱性等訊息，已有實測結果證明在厚度僅單層晶格之極限狀態下，依然可以取得足夠強度對比之繞射訊號來分析其磊晶狀態及對稱模式。同時，X光反射光譜可以提供連續單元子層二維材料關於厚度，粗糙度，密度等重要訊息，對於非連續性二維材料之分佈及覆蓋率亦能提供相對趨勢，為十分重要且具發展性的分析技術。

2D material is one of best candidate for new generation of semiconductor owing to its excellent electric and optical properties. However, it’s difficult to illustrate its crystal structure and properties because of its mono layer structure. NSRRC is an advanced synchrotron instrument that provide X-ray beam with high quality and high brightness. X-ray diffraction beamline (TLS BL-17B1) is a powerful beamline that designed for epitaxial or nanostructure to provide information of crystal state, strain state and symmetry structure of one unit cell of 2D materials. Moreover, X-ray reflectivity is another useful technology that could measure and illustrate the thickness, roughness and density of mono-layer structure of non-continuous 2D materials. It’s also be found that the trend of coverage rate could also be tracked by XRR technology.