Manipulation of carriers in graphene using an on-chip acoustic wave device

In this paper, we fabricated a hybrid on-chip acoustic and field-effect device to investigate the acoustic carrier transportation in graphene. The device fabrication exploited aluminum nitride (AlN)-based surface micromachining process on a silicon wafer, facilitating an integration of a surface acoustic wave (SAW) delay line and a graphene field-effect transistor (GFET). The SAW device induced an acousto-electric (AE) current in graphene, which scales linearly with the input power and remains essentially constant when subtracting the offset current at different DC biases. At a constant DC bias, the AE current can be modulated by the gate voltage, due to the change of the carrier mobility in graphene. The integrated device provides a powerful tool to understand the AE current in graphene, and it opens an avenue to explore the properties of diverse nanomaterials.