Tag Archives: graphene-based microphone

A very sensitive graphene microphone

The researchers have not made a complete graphene-based microphone yet but they do have a proof-of-concept according a Nov. 26, 2015 Institute of Physics news release on EurekAlert,

Scientists have developed a graphene based microphone nearly 32 times more sensitive than microphones of standard nickel-based construction.

The researchers, based at the University of Belgrade, Serbia, created a vibrating membrane – the part of a condenser microphone which converts the sound to a current – from graphene, and were able to show up to 15 dB higher sensitivity compared to a commercial microphone, at frequencies up to 11 kHz.

“We wanted to show that graphene, although a relatively new material, has potential for real world applications” explains Marko Spasenovic, an author of the paper. “Given its light weight, high mechanical strength and flexibility, graphene just begs to be used as an acoustic membrane material.”

The graphene membrane, approximately 60 layers thick, was grown on a nickel foil using chemical vapour deposition, to ensure consistent quality across all the samples.

During membrane production, the nickel foil was etched away and the graphene membrane placed in the same housing as a commercial microphone for comparison. This showed a 15 dB higher sensitivity than the commercial microphone.

The researchers also simulated a 300-layer thick graphene membrane, which shows potential for performance far into the ultrasonic part of the spectrum.

“The microphone performed as well as we hoped it would” adds Spasenovic. “A thicker graphene membrane theoretically could be stretched further, enabling ultrasonic performance, but sadly we’re just not quite there yet experimentally.”

“At this stage there are several obstacles to making cheap graphene, so our microphone should be considered more a proof of concept” [emphasis mine] concludes Spasenovic. “The industry is working hard to improve graphene production – eventually this should mean we have better microphones at lower cost.”

There is a video abstract (the first time I’ve seen one of these)  for the research paper: http://bcove.me/5vfn17jb

Here’s a link to and a citation for the paper,

Multilayer graphene condenser microphone by Dejan Todorović, Aleksandar Matković, Marijana Milićević, Djordje Jovanović, Radoš Gajić, Iva Salom, and Marko Spasenović. 2D Materials, Volume 2, Number 4 doi.org/10.1088/2053-1583/2/4/045013  Published 26 November 2015

© 2015 IOP Publishing Ltd

This paper is behind a paywall.