Graphene membrane makes for a more sensitive condenser microphone

A proof of concept microphone constructed with a graphene membrane has been found to be more sensitive than conventional microphones(Credit: Shutterstock)

Graphene's ever-growing list of remarkable properties has seen many wide-reaching potential applications for the wonder material proposed, but actual demonstrations of real-world uses are still thin on the ground. But that's slowly changing. Following a graphene-based light bulb headed for commercial release being revealed earlier this year, now scientists have developed a graphene-based condenser microphone that is more sensitive than its conventional cousins.

The research team at the University of Belgrade in Serbia started by growing a graphene membrane around 60 layers thick on a nickel foil substrate using a chemical vapour deposition process. They then etched the nickel foil away and placed the remaining graphene membrane in a microphone housing to act as the vibrating membrane in condenser microphones that converts sound to an electrical current.

The housing was those used in microphones with a standard nickel-based construction so as to allow for a direct comparison between the two. The researchers found that the graphene-based microphone was up to 15 dB more sensitive at frequencies up to 11 kHz than a commercial microphone. However, the researchers say simulations they conducted for a 300-layer thick graphene membrane, which could theoretically be stretched further, suggests sensitivity could potentially be increased to far into the ultrasonic part of the spectrum.

"We wanted to show that graphene, although a relatively new material, has potential for real world applications" says 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."

However, Spasenovic stressed the team's microphone is only a proof of concept due to difficulties surrounding graphene production. But given the rapid strides being made in this area, his vision of microphones with higher sensitivity being available for lower cost may become a reality sooner rather than later.

The results of the team's research appear in the journal 2D materials.

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