Aggoune Wahib, Cocchi Caterina, Nabok Dmitrii, Rezouali Karim, Akli Belkhir Mohamed, Draxl Claudia
Institut für Physik and IRIS Adlershof, Humboldt-Universität zu Berlin , 12489 Berlin, Germany.
Laboratoire de Physique Théorique, Faculté des Science Exactes, Université de Bejaia , 06000 Bejaia, Algeria.
J Phys Chem Lett. 2017 Apr 6;8(7):1464-1471. doi: 10.1021/acs.jpclett.7b00357. Epub 2017 Mar 20.
By investigating the optoelectronic properties of prototypical graphene/hexagonal boron nitride (h-BN) heterostructures, we demonstrate how a nanostructured combination of these materials can lead to a dramatic enhancement of light-matter interaction and give rise to unique excitations. In the framework of ab initio many-body perturbation theory, we show that such heterostructures absorb light over a broad frequency range, from the near-infrared to the ultraviolet (UV), and that each spectral region is characterized by a specific type of excitations. Delocalized electron-hole pairs in graphene dominate the low-energy part of the spectrum, while strongly bound electron-hole pairs in h-BN are preserved in the near-UV. Besides these features, characteristic of the pristine constituents, charge-transfer excitations appear across the visible region. Remarkably, the spatial distribution of the electron and the hole can be selectively tuned by modulating the stacking arrangement of the individual building blocks. Our results open up unprecedented perspectives in view of designing van der Waals heterostructures with tailored optoelectronic features.
通过研究典型的石墨烯/六方氮化硼（h-BN）异质结构的光电特性，我们展示了这些材料的纳米结构组合如何能够显著增强光与物质的相互作用并产生独特的激发态。在从头算多体微扰理论的框架下，我们表明这种异质结构在从近红外到紫外（UV）的宽频率范围内吸收光，并且每个光谱区域都以特定类型的激发为特征。石墨烯中的离域电子-空穴对主导了光谱的低能量部分，而h-BN中强束缚的电子-空穴对则保留在近紫外区域。除了这些原始组分的特征外，电荷转移激发出现在整个可见光区域。值得注意的是，通过调节各个构建块的堆叠排列，可以选择性地调整电子和空穴的空间分布。鉴于设计具有定制光电特性的范德华异质结构，我们的结果开辟了前所未有的前景。
