State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China.
Department of Chemistry and Biochemistry and California Nanosystems Institute, University of California, Los Angeles, CA 90095, USA.
Science. 2017 Aug 25;357(6353):788-792. doi: 10.1126/science.aan6814. Epub 2017 Aug 3.
We report a general synthetic strategy for highly robust growth of diverse lateral heterostructures, multiheterostructures, and superlattices from two-dimensional (2D) atomic crystals. A reverse flow during the temperature-swing stage in the sequential vapor deposition growth process allowed us to cool the existing 2D crystals to prevent undesired thermal degradation and uncontrolled homogeneous nucleation, thus enabling highly robust block-by-block epitaxial growth. Raman and photoluminescence mapping studies showed that a wide range of 2D heterostructures (such as WS-WSe and WS-MoSe), multiheterostructures (such as WS-WSe-MoS and WS-MoSe-WSe), and superlattices (such as WS-WSe-WS-WSe-WS) were readily prepared with precisely controlled spatial modulation. Transmission electron microscope studies showed clear chemical modulation with atomically sharp interfaces. Electrical transport studies of WSe-WS lateral junctions showed well-defined diode characteristics with a rectification ratio up to 10.
我们报告了一种通用的合成策略，用于从二维（2D）原子晶体中高度稳健地生长各种横向异质结构、多异质结构和超晶格。在顺序气相沉积生长过程中的温度摆动阶段的反向流动允许我们冷却现有的 2D 晶体，以防止不必要的热降解和不受控制的均相成核，从而实现高度稳健的逐块外延生长。拉曼和光致发光映射研究表明，很容易制备出各种 2D 异质结构（如 WS-WSe 和 WS-MoSe）、多异质结构（如 WS-WSe-MoS 和 WS-MoSe-WSe）和超晶格（如 WS-WSe-WS-WSe-WS），具有精确控制的空间调制。透射电子显微镜研究表明，具有原子级锐利界面的化学调制清晰可见。WSe-WS 横向结的电输运研究表明，具有高达 10 的整流比的良好定义的二极管特性。
