Electronic structure evolution induced by a monolayer gold in silicide-embedded silicon nanowires

Chia-Yi Wu^1*, Jia-An Lin², Yi-Chia Chou¹

¹Department of Materials Science and Engineering, National Taiwan University, Taipei, Taiwan
²Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan

* Presenter:Chia-Yi Wu, email:chiayiwu@ntu.edu.tw

Two-dimensional (2D) metals have attracted great attention due to their vast field of potential applications. Compared to other metals, gold is believed to be easier to form into the 2D nanosheet because of its lower surface energy.[1] 2D gold has been successfully synthesized recently.[2] The high intrinsic conductivity of 2D gold positions it as a promising candidate to replace graphene.[3] In this work, we used atomic-scale scanning transmission electron microscopy (STEM) and energy electron loss spectroscopy (EELS) to characterize the epitaxial monolayer gold in the NiSi₂-embedded nanowires. The presence of monolayer Au and the interface structure of NiSi₂/monolayer Au/Si were confirmed using STEM, energy-dispersive X-ray spectroscopy (EDS), and QSTEM simulations. Combined with simulated results, we found that the interrupting by the gold layer might cause the stronger coupling of Ni and Si atoms. It might influence the covalency of the chemical bonds between Ni and Si atoms at the NiSi₂/Si interface.


Reference
[1] S. Yu, C. Zhang, H. Yang, Chemical Reviews 123(7) (2023) 3443-3492.
[2] S. Kashiwaya, Y. Shi, J. Lu, D.G. Sangiovanni, G. Greczynski, M. Magnuson, M. Andersson, J. Rosen, L. Hultman, Nature Synthesis 3(6) (2024) 744-751.
[3] S. Zhao, H. Zhang, M. Zhu, L. Jiang, Y. Zheng, Physical Review B 110(8) (2024) 085111.

Keywords: Two-dimensional metals, Silicon nanowires, Energy electron loss spectroscopy, Electronic structure, Nickel silicide