Kim Hyo Won, Ko Wonhee, Joo Won-Jae, Cho Yeonchoo, Oh Youngtek, Ku JiYeon, Jeon Insu, Park Seongjung, Hwang Sung Woo
Samsung Advanced Institute of Technology , Suwon 16678 , Korea.
J Phys Chem Lett. 2018 Dec 20;9(24):7059-7063. doi: 10.1021/acs.jpclett.8b03315. Epub 2018 Dec 6.
The direct growth of graphene on a semiconducting substrate opens a new avenue for future graphene-based applications. Understanding the structural and electronic properties of the graphene on a semiconducting surface is key for realizing such structures; however, these properties are poorly understood thus far. Here, we provide insight into the structural and electronic properties of graphene grown directly on a Ge(110) substrate. Our scanning tunneling microscopy (STM) study reveals that overlaying graphene on Ge(110) promotes the formation of a new Ge surface reconstruction, i.e., a (6 × 2) superstructure, which has been never observed for a bare Ge(110) surface. The electronic properties of the system exhibit the characteristics of both graphene and Ge. The differential conductance (d I/d V) spectrum from a scanning tunneling spectroscopy (STS) study bears a parabolic structure, corresponding to a reduction in the graphene Fermi velocity, exhibiting additional peaks stemming from the p-orbitals of Ge. The density functional theory (DFT) calculations confirm the existence of surface states due to the p-orbitals of Ge.
石墨烯在半导体衬底上的直接生长为未来基于石墨烯的应用开辟了一条新途径。了解石墨烯在半导体表面的结构和电子特性是实现此类结构的关键；然而，迄今为止对这些特性的了解还很有限。在此，我们深入研究了直接生长在Ge(110)衬底上的石墨烯的结构和电子特性。我们的扫描隧道显微镜（STM）研究表明，在Ge(110)上覆盖石墨烯会促进形成一种新的Ge表面重构，即(6×2)超结构，这在裸露的Ge(110)表面从未被观察到。该系统的电子特性展现出石墨烯和Ge两者的特征。扫描隧道谱（STS）研究得到的微分电导（dI/dV）谱呈现出抛物线结构，这对应于石墨烯费米速度的降低，同时还展现出来自Ge的p轨道的额外峰。密度泛函理论（DFT）计算证实了由于Ge的p轨道而存在表面态。
