MRS Meetings and Events

 

NM07.09.02 2022 MRS Fall Meeting

Optical Properties of Xene Heterostructures Grown by MBE

When and Where

Dec 1, 2022
8:00am - 8:15am

Hynes, Level 2, Room 203

Presenter

Co-Author(s)

Alessandro Molle1,Eleonora Bonaventura1,2,Daya Sagar Dhungana1,Christian Martella1,Salvatore Macis3,Stefano Lupi3,Emiliano Bonera2,Carlo Grazianetti1

Consiglio Nazionale delle Ricerche1,Università degli Studi di Milano-Bicocca2,Sapienza - Università di Roma3

Abstract

Alessandro Molle1,Eleonora Bonaventura1,2,Daya Sagar Dhungana1,Christian Martella1,Salvatore Macis3,Stefano Lupi3,Emiliano Bonera2,Carlo Grazianetti1

Consiglio Nazionale delle Ricerche1,Università degli Studi di Milano-Bicocca2,Sapienza - Università di Roma3
The dimensional reduction brought by the advent of two-dimensional (2D) materials opened new routes for nanoelectronics and photonics applications. In this framework, the Xenes (artificial graphene-like monoelemental lattices) represented a new forefront because of their peculiarities [1]. Unfortunately, the high chemical reactivity and the strong hybridization effects with the native substrates limited their use to date: silicene on silver and tin on sapphire are two of the most striking examples in this respect. Despite the different nature of the above-mentioned substrates - metallic silver and insulating sapphire - their effect on the properties of Xenes is an intriguing framework where the epitaxial growth of the Xenes can be engineered by <i>ad hoc</i> processes. While the hybridization between the electronic states of silicene and the underlying silver are predominant in the former case [2], oxidation effects occur in the latter due to the reactivity of tin [3]. For these reasons, the Xene-based heterostructure concept takes on a certain relevance [4]. Vertical stacks of different layers of atomically thin crystals enable to create novel structures and in turn to control their electronic properties. Such stacks, in a close analogy to the van der Waals heterostructures, could offer an unprecedented degree of freedom in discovering new functionalities. Here, we report on the optical properties of new Xenes-based configurations, i.e. silicene-stanene on Ag(111) and stanene-graphene on Al2O3(0001), made accessible by spectroscopic measurements in the MIR-UV spectral range (from 0.12 to 6.5 eV) and Raman spectroscopy measurements. Our results highlight the role of the inter-layer in electronically and chemically decoupling the on top Xene from the native substrate, resulting in a different response when two layers are combined. The decoupling effect for silicene on stanene is studied in terms of the photo-thermal Raman response, revealing stark differences in the heat transport properties of single layer epitaxial Xenes and heterostructures [5]. In the case of stanene on graphene, X-ray photoelectron spectroscopy shows an effective role of graphene to avoid tin oxidation, whereas the optical analysis discloses an intriguing response from the tin layer different from that grown directly in contact with the Al2O3(0001) substrate. Finally, our findings support the possibility of tuning the well-known plasmonic response of either silver or graphene by combining different atomically thin layers on their surface.<br/>[1] A. Molle, J. Goldberger, M. Houssa, Y. Xu, S.-C. Zhang and D. Akinwande, Nat. Mater., 2017, 16, 163–169.<br/>[2] E. Cinquanta, G. Fratesi, S. Dal Conte, C. Grazianetti, F. Scotognella, S. Stagira, C. Vozzi, G. Onida and A. Molle, Phys. Rev. B - Condens. Matter Mater. Phys., 2015, 92, 165427.<br/>[3] C. Grazianetti, E. Bonaventura, C. Martella, A. Molle and S. Lupi, <i>ACS Appl. Nano Mater.</i>, 2021, <b>4</b>, 2351–2356.<br/>[4] D. S. Dhungana, C. Grazianetti, C. Martella, S. Achilli, G. Fratesi and A. Molle, Adv. Funct. Mater., 2021, 31, 2102797.<br/>[5] E. Bonaventura, D. S. Dhungana, C. Martella, C. Grazianetti, S. Macis, S. Lupi, E. Bonera, A. Molle, submitted.

Keywords

optical properties | thermal conductivity

Symposium Organizers

Jeehwan Kim, Massachusetts Institute of Technology
Sanghoon Bae, Washington University in Saint Louis
Deep Jariwala, University of Pennsylvania
Kyusang Lee, University of Virginia

Publishing Alliance

MRS publishes with Springer Nature