Surface Acoustic Wave Amplification by DC-Voltage Supplied to Graphene Film

TL;DR

This study demonstrates that applying a DC voltage to a graphene film on a piezoelectric crystal significantly amplifies surface acoustic waves, with measurable increases in diffraction satellite intensity at 471 MHz.

Contribution

First experimental demonstration of SAW amplification via DC voltage applied to graphene on a piezoelectric crystal, supported by theoretical analysis.

Findings

Amplification of 33.2 dB/cm for satellite +1 at 471 MHz

Amplification of 13.8 dB/cm for satellite +2 at 471 MHz

SAW amplification occurs at lower DC fields than in bulk semiconductor systems

Abstract

Using a high-resolution X-Ray diffraction measurement method, the surface acoustic waves (SAW) propagation in a graphene film on the surface of a Ca3TaGa3Si2O14 (CTGS) piezoelectric crystal was investigated, where an external current was driven across the graphene film. Here we show for the first time that the application of the DC field leads to a significant enhancement of the SAW magnitude and, as a result, to amplification of the diffraction satellites. Amplification of 33.2 dB/cm for the satellite +1, and of 13.8 dB/cm for the satellite +2, at 471 MHz has been observed where the external DC voltage of +10V was applied. Amplification of SAW occurs above a DC field much smaller than that of a system using bulk semiconductor. Theoretical estimates are in reasonable agreement with our measurements and analysis of experimental data for other materials.