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HL: Fachverband Halbleiterphysik
HL 14: 2D Materials III (joint session HL/CPP)
HL 14.4: Talk
Tuesday, March 28, 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 Syed3,4, 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