Borophene synthesis beyond the single-atomic-layer limit
Borophene synthesis beyond the single-atomic-layer limit
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DOI：
10.1038/s41563-021-01084-2
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发表时间：
2021-08-26
期刊：
影响因子：
41.2
通讯作者：
Hersam, Mark C.
中科院分区：
文献类型：
--
作者：
Liu, Xiaolong;Li, Qiucheng;Hersam, Mark C.
合成二维（2D）材料没有大块对应物，并且由于衬底稳定生长而通常作为单原子层存在。多层膜的形成，虽然广泛寻求结构和性能调整，尚未实现的情况下，合成2D硼：即，硼氢化物（1，2）。在这里，我们通过实验证明了一个原子定义的硼多晶型超出单原子层（SL）的限制的合成。这种双层（BL）硼化物的结构是一致的两个共价键合的α-相层（称为BL-α硼化物），从键分辨扫描隧道显微镜，非接触式原子力显微镜和密度泛函理论计算证明。虽然BL-α硼化物费米能级附近的电子态密度与SL硼化物多晶型物相似，但场发射共振光谱显示出明显的界面电荷转移掺杂和超过5 eV的升高的局部功函数。硼化物多晶型物超过SL极限的延伸显著地扩展了硼基纳米材料的相空间。
Synthetic two-dimensional (2D) materials have no bulk counterparts and typically exist as single atomic layers due to substrate-stabilized growth. Multilayer formation, although broadly sought for structure and property tuning, has not yet been achieved in the case of synthetic 2D boron: that is, borophene(1,2). Here, we experimentally demonstrate the synthesis of an atomically well-defined borophene polymorph beyond the single-atomic-layer (SL) limit. The structure of this bilayer (BL) borophene is consistent with two covalently bonded alpha-phase layers (termed BL-alpha borophene) as evidenced from bond-resolved scanning tunnelling microscopy, non-contact atomic force microscopy and density functional theory calculations. While the electronic density of states near the Fermi level of BL-alpha borophene is similar to SL borophene polymorphs, field-emission resonance spectroscopy reveals distinct interfacial charge transfer doping and a heightened local work function exceeding 5 eV. The extension of borophene polymorphs beyond the SL limit significantly expands the phase space for boron-based nanomaterials.