Li Linfei, Schultz Jeremy F, Mahapatra Sayantan, Liu Xiaolong, Zhang Xu, Hersam Mark C, Jiang Nan
Department of Chemistry, University of Illinois Chicago, Chicago, IL 60607, USA.
Department of Physics and Astronomy, University of Notre Dame, Notre Dame, IN 46556, USA.
Angew Chem Int Ed Engl. 2023 Aug 7;62(32):e202306590. doi: 10.1002/anie.202306590. Epub 2023 Jun 30.
Bilayer (BL) two-dimensional boron (i.e., borophene) has recently been synthesized and computationally predicted to have promising physical properties for a variety of electronic and energy technologies. However, the fundamental chemical properties of BL borophene that form the foundation of practical applications remain unexplored. Here, we present atomic-level chemical characterization of BL borophene using ultrahigh vacuum tip-enhanced Raman spectroscopy (UHV-TERS). UHV-TERS identifies the vibrational fingerprint of BL borophene with angstrom-scale spatial resolution. The observed Raman spectra are directly correlated with the vibrations of interlayer boron-boron bonds, validating the three-dimensional lattice geometry of BL borophene. By virtue of the single-bond sensitivity of UHV-TERS to oxygen adatoms, we demonstrate the enhanced chemical stability of BL borophene compared to its monolayer counterpart by exposure to controlled oxidizing atmospheres in UHV. In addition to providing fundamental chemical insight into BL borophene, this work establishes UHV-TERS as a powerful tool to probe interlayer bonding and surface reactivity of low-dimensional materials at the atomic scale.
双层（BL）二维硼（即硼烯）最近已被合成出来，并且通过计算预测其在各种电子和能源技术方面具有良好的物理性能。然而，构成实际应用基础的BL硼烯的基本化学性质仍未得到探索。在此，我们使用超高真空针尖增强拉曼光谱（UHV - TERS）对BL硼烯进行了原子级化学表征。UHV - TERS以埃级空间分辨率识别出BL硼烯的振动指纹。观察到的拉曼光谱与层间硼 - 硼键的振动直接相关，验证了BL硼烯的三维晶格几何结构。借助UHV - TERS对氧吸附原子的单键敏感性，我们通过在超高真空环境中暴露于可控氧化气氛，证明了BL硼烯与其单层对应物相比具有更高的化学稳定性。除了为BL硼烯提供基本的化学见解外，这项工作还将UHV - TERS确立为一种在原子尺度上探测低维材料层间键合和表面反应性的强大工具。
