单层及双层石墨烯内亚稳态二维六方碘化亚铜的底向上合成
Bottom-up Synthesis of Metastable 2D Hexagonal Copper(I) Iodide on Monolayer and within Bilayer Graphene
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中文总结 AI 辅助
本研究通过气相法在石墨烯上低温合成亚稳态二维六方碘化亚铜，利用铜网格和HI蒸气实现选择性成核与生长，为宽带隙器件提供新途径。
中文摘要 AI 辅助
碘化亚铜（CuI）是一种宽带隙半导体，在环境条件下结晶为三维γ相；其层状范德华体相β-CuI仅在643至673 K之间稳定。二维（2D）h-CuI形态已通过液相剥离机械化学制备的前驱体以及石墨烯片层间封装获得，但尚未在开放表面上实现2D h-CuI的底向上生长。在此，我们报道了一种气相合成方法，在低温下直接在低缺陷、大面积单层及双层还原氧化石墨烯（r-oxo-G）内生长h-CuI。使用铜TEM网格作为铜的固态前驱体，在40°C下暴露于HI蒸气引发成核，而在180°C下退火促进扩展h-CuI畴的生长。像差校正HRTEM解析了CuI/r-oxo-G纳米杂化物的原子结构、局部扭转角和晶格各向异性，而STEM-EDX得出Cu:I比与1:1一致。第一性原理计算表明，与石墨烯的范德华粘附稳定了支撑的六方层。在所提出的低温前驱体条件下，γ相成核路径不可用，使得六方相在石墨烯界面处选择性形成。从头算分子动力学模拟表明，异质结构在600 K下保持其六方晶格有序性，包括在开放的单层石墨烯支撑上。生长的横向范围主要受剩余界面吸附物的限制。这些结果确立了在化学惰性石墨烯模板上制备亚稳态2D h-CuI的途径，这可能对宽带隙电子和光电器件有用。
英文摘要
Copper(I) iodide (CuI) is a wide-bandgap semiconductor crystallizing in the 3D $γ$-phase under ambient conditions; its layered van der Waals bulk phase $β$-CuI is stable only between 643 and 673 K. The two-dimensional (2D) h-CuI form has been obtained via liquid-phase exfoliation of mechanochemically prepared precursors and via encapsulation between graphene sheets, whereas bottom-up growth of 2D h-CuI on open surfaces has not yet been demonstrated. Here, we report a vapor-phase synthesis of h-CuI directly on low-defect, large-area monolayer and within bilayer reduced oxo-graphene (r-oxo-G) at low temperatures. Using a copper TEM grid as the solid-state precursor for copper, HI-vapor exposure at 40 $°$C initiates nucleation, while annealing at 180 $°$C promotes the growth of extended h-CuI domains. Aberration-corrected HRTEM resolves the atomic structure, local twist angles, and lattice anisotropy of the CuI/r-oxo-G nanohybrid, while STEM-EDX yields a Cu:I ratio consistent with 1:1. First-principles calculations show that van der Waals adhesion to graphene stabilizes the supported hexagonal layer. Under the presented low-temperature precursor conditions, pathways for nucleation of the $γ$-phase are not available, allowing the hexagonal phase to form selectively at the graphene interface. Ab initio molecular dynamics simulations show that the heterostructure retains its hexagonal lattice order at 600 K, including on an open monolayer graphene support. The lateral extent of the growth is limited mainly by remaining interfacial adsorbates. These results establish a route to metastable 2D h-CuI on a chemically inert graphene template, which may be useful for wide-bandgap electronic and optoelectronic devices.
发表机构
- Friedrich Schiller University Jena（耶拿弗里德里希·席勒大学）
- Leibniz Institute of Photonic Technology (Leibniz-IPHT)（莱布尼茨光子技术研究所）
- Ulm University（乌尔姆大学）
- University of Nottingham（诺丁汉大学）
- Freie Universität Berlin（柏林自由大学）
- Leibniz Institute of Surface Engineering (IOM)（莱布尼茨表面工程研究所）
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