Cui Xingxia, Han Ding, Guo Hongli, Zhou Linwei, Qiao Jingsi, Liu Qing, Cui Zhihao, Li Yafei, Lin Chungwei, Cao Limin, Ji Wei, Petek Hrvoje, Feng Min
School of Physics and Technology and Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education, Wuhan University, Wuhan, 430072, China.
Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing, 100872, China.
Nat Commun. 2019 Jul 29;10(1):3374. doi: 10.1038/s41467-019-11300-y.
Collective molecular physical properties can be enhanced from their intrinsic characteristics by templating at material interfaces. Here we report how a black phosphorous (BP) substrate concatenates a nearly-free-electron (NFE) like conduction band of a C monolayer. Scanning tunneling microscopy reveals the C lowest unoccupied molecular orbital (LUMO) band is strongly delocalized in two-dimensions, which is unprecedented for a molecular semiconductor. Experiment and theory show van der Waals forces between C and BP reduce the inter-C distance and cause mutual orientation, thereby optimizing the π-π wave function overlap and forming the NFE-like band. Electronic structure and carrier mobility calculations predict that the NFE band of C acquires an effective mass of 0.53-0.70 m (m is the mass of free electrons), and has carrier mobility of ~200 to 440 cmVs. The substrate-mediated intermolecular van der Waals interactions provide a route to enhance charge delocalization in fullerenes and other organic semiconductors.
通过在材料界面进行模板化，集体分子物理性质可以从其固有特性得到增强。在此我们报告黑磷（BP）衬底如何连接碳单层的近自由电子（NFE）类导带。扫描隧道显微镜显示碳的最低未占据分子轨道（LUMO）带在二维中强烈离域，这对于分子半导体来说是前所未有的。实验和理论表明，碳与黑磷之间的范德华力减小了碳 - 碳间距并导致相互取向，从而优化了π - π波函数重叠并形成了NFE类带。电子结构和载流子迁移率计算预测，碳的NFE带获得了0.53 - 0.70m的有效质量（m为自由电子质量），并且载流子迁移率约为200至440cm²V⁻¹s⁻¹。衬底介导的分子间范德华相互作用为增强富勒烯和其他有机半导体中的电荷离域提供了一条途径。
