Passivating Graphene and Suppressing Interfacial Phonon Scattering with Mechanically Transferred Large-Area Ga2O3

Matthew Gebert; Semonti Bhattacharyya; Christopher C Bounds; Nitu Syed; Torben Daeneke; Michael S Fuhrer

doi:10.1021/acs.nanolett.2c03492

Passivating Graphene and Suppressing Interfacial Phonon Scattering with Mechanically Transferred Large-Area Ga₂O₃

Nano Lett. 2023 Jan 11;23(1):363-370. doi: 10.1021/acs.nanolett.2c03492. Epub 2022 Nov 21.

Authors

Matthew Gebert^{1

2}, Semonti Bhattacharyya^{1

2

3}, Christopher C Bounds¹, Nitu Syed^{4

5}, Torben Daeneke^{5

6}, Michael S Fuhrer^{1

2}

Affiliations

¹ School of Physics and Astronomy, Monash University, Melbourne, Victoria 3800, Australia.
² ARC Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Melbourne, Victoria 3800, Australia.
³ Leiden Institute of Physics, Leiden University, Niels Bohrweg 2, 2333 CA, Leiden, The Netherlands.
⁴ School of Physics, The University of Melbourne, Parkville, Melbourne, Victoria 3010, Australia.
⁵ School of Engineering, RMIT University, Melbourne, Victoria 3000, Australia.
⁶ ARC Centre of Excellence in Future Low-Energy Electronics Technologies, RMIT University, Melbourne, Victoria 3000, Australia.

Abstract

We demonstrate a large-area passivation layer for graphene by mechanical transfer of ultrathin amorphous Ga₂O₃ synthesized on liquid Ga metal. A comparison of temperature-dependent electrical measurements of millimeter-scale passivated and bare graphene on SiO₂/Si indicates that the passivated graphene maintains its high field effect mobility desirable for applications. Surprisingly, the temperature-dependent resistivity is reduced in passivated graphene over a range of temperatures below 220 K, due to the interplay of screening of the surface optical phonon modes of the SiO₂ by high-dielectric-constant Ga₂O₃ and the relatively high characteristic phonon frequencies of Ga₂O₃. Raman spectroscopy and electrical measurements indicate that Ga₂O₃ passivation also protects graphene from further processing such as plasma-enhanced atomic layer deposition of Al₂O₃.

Keywords: “chemical vapor deposition (CVD) graphene”; “dielectric screening”; “mm-scale oxide dielectric”; “passivation”; “remote interfacial polar phonon scattering”; “van der Waals heterostructure”.