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HL: Fachverband Halbleiterphysik

HL 14: 2D Materials III (joint session HL/CPP)

HL 14.4: Vortrag

Dienstag, 28. März 2023, 10:15–10:30, POT 81

Tuning electronic properties of graphene with a transferred ultrathin Ga₂O₃ encapsulation — Matthew Gebert¹, •Semonti Bhattacharyya², Christopher Bounds¹, Nitu Syed^3,4, Torben Daeneke⁴, and Michael S. Fuhrer¹ — ¹School of Physics and Astronomy, Monash University, Melbourne — ²Leiden Institute of Physics, Leiden University, Leiden — ³School of Physics, The University of Melbourne, Parkville, Melbourne — ⁴School of Engineering, RMIT University, Melbourne

Although graphene holds immense potential for future electronics and spintronics, it is tricky to find a suitable large-area encapsulation layer for graphene that enhances its properties. In this talk, I will demonstrate a large-area passivation layer for graphene by mechanical transfer of ultrathin Ga₂O₃ synthesized on the surface of liquid Ga metal.¹

Electrical measurements of millimetre-scale passivated and bare CVD graphene on SiO₂ substrate indicate that the passivated graphene maintains its high field effect mobility, desirable for applications. Surprisingly, the temperature-dependent resistivity is reduced in our passivated graphene over a range of temperatures below 230 K, due to the interplay of screening of the remote optical phonon modes of the SiO₂ by the high dielectric constant of 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.

1. Gebert, Bhattacharyya et al, Nano Lett, https://doi.org/10.1021/acs.nanolett.2c03492