02.12.15

Mic goes ultrasonic using graphene

Researchers have developed a microphone with a graphene membrane that has the potential to be 32 times more sensitive than standard microphones that use nickel membranes. The project was a collaborative effort between Dejan Todorović of the Serbia-based consultancy Dirigent Acoustics and scientists at the University of Belgrade. The team say the development has created one of the world’s smallest microphones that will open up new opportunities in acoustic design.

Most professional microphones use a moving membrane that senses and records sound as the human ear does. Most products on the market currently use microscopic nickel or plastic membranes as  these materials are lightweight, strong and flexible.

With its mechanical strength and extremely light weight, graphene has been considered a good choice to replace the currently used materials in microphones. The membrane used in this experiment was just 25 nanometres thin, and performed at least as well as microphones that use nickel.

The researchers calculated that the membrane could be pulled tighter to enable it to perform in the ultrasonic part of the spectrum. Because graphene can sustain strong lateral pulling forces, their calculations showed that pulling a 300-layer thick membrane near to its breaking threshold would push the frequency up to 1MHZ.

“Having such a compact ultrasonic microphone would be great for various branches of the industry,” they said, in a video published with a research paper published on 2D Materials. “We’re not there yet but we have the concept and we can work from here to improve it.”