Acousto-electric measurements at 2.5 GHz on graphene transferred onto YX128°-LiNbO₃

Abstract

Surface acoustic wave delay lines with operational frequency of 2.5 GHz have been designed to measure the acousto-electronic transport of carriers in graphene transferred onto YX128°-LiNbO3 piezoelectric substrate. The monolayer of graphene on LiNbO3 presented sheet resistance in the range of 733 to 1230 Ω/□ and ohmic contact resistance with gold of 1880 to 5200 Ωµm. The measurements with different interaction lengths on graphene bars have allowed to extract carrier absorption and mobility parameters from acousto-electric current. Graphene presented higher acousto-electronic interaction in the GHz range than previously reported values in the range of 100s MHz with carrier absorption losses of 109 m-1 and a mobility for acoustically generated charges of 101 cm2/Vs.