Ultra-sensitive graphene membranes for microphone applications

TL;DR

This paper demonstrates that multilayer graphene membranes exhibit significantly higher mechanical sensitivity and lower detection limits compared to traditional MEMS microphones, promising advancements in miniaturized acoustic sensing devices.

Contribution

The study provides a comprehensive laser vibrometry analysis of graphene membranes, highlighting their superior sensitivity and lower detection thresholds for microphone applications.

Findings

Graphene membranes have over 100 times higher compliance than MEMS microphones.

Achieved a detection limit as low as 15 dBSPL, outperforming current MEMS devices.

Identified trade-offs and limitations in graphene microphone design.

Abstract

Microphones exploit the motion of suspended membranes to detect sound waves. Since the microphone performance can be improved by reducing the thickness and mass of its sensing membrane, graphene-based microphones are expected to outperform state-of-the-art microelectromechanical (MEMS) microphones and allow further miniaturization of the device. Here, we present a laser vibrometry study of the acoustic response of suspended multilayer graphene membranes for microphone applications. We address performance parameters relevant for acoustic sensing, including mechanical sensitivity, limit of detection and nonlinear distortion, and discuss the trade-offs and limitations in the design of graphene microphones. We demonstrate superior mechanical sensitivities of the graphene membranes, reaching more than 2 orders of magnitude higher compliances than commercial MEMS devices, and report a limit of detection as low as 15 dBSPL, which is 10 - 15 dB lower than that featured by current MEMS microphones.