We report a novel fabrication method of graphene Al2O3 gate insulators based on sputtering. Electrical performance of dual-gated mono- and bilayer exfoliated graphene devices is presented. Sputtered Al2O3 layers possess comparable quality to oxides obtained by atomic layer deposition (ALD) with respect to a high relative dielectric constant of about 8, as well as low-hysteresis performance and high breakdown voltage. We observe a moderate carrier mobility of about 1000 cm2/Vs in graphene and 350 cm2/Vs in its bilayer due to increased resonant scattering on atomic scale defects. Most likely this originated from the thin Al precursor layer evaporated prior to sputtering the Al2O3 gate oxide.
@article{arxiv.1110.1535,
title = {Versatile sputtering technology for Al2O3 gate insulators on graphene},
author = {M. Friedemann and M. Woszczyna and A. Müller and S. Wundrack and T. Dziomba and Th. Weimann and Th. Seyller and F. Ahlers},
journal= {arXiv preprint arXiv:1110.1535},
year = {2015}
}