Ultrasonic Microphones: New Graphene Microphone Is 32x More Sensitive
At this point, I think that it is safe to say that graphene can pretty much do anything—and it can do it better than most other materials.
If we needed further proof of this, we just got it.
Scientists from the University of Belgrade, Serbia have developed a microphone made from graphene, and according to the paper, it’s 32 times more sensitive than standard nickel-based microphones. At frequencies up to 11 kHz, the new microphone’s graphene-based vibrating membrane is capable of showing up to 15 dB higher sensitivity than that of commercial microphones.
Ultimately, it could detect sounds that are beyond the range of human hearing.
Author Marko Spasenovic explained the purpose of utilizing a relatively new material for real world applications, saying “Given its light weight, high mechanical strength and flexibility, graphene just begs to be used as an acoustic membrane material.”
If you aren’t aware, this amazing material is about 200x more electrically conductive than silicon and 10x more thermally conductive than copper. Also, a single layer of graphene is about 100 times stronger than steel, yet extremely flexible. One of the reasons why graphene is so strong is because its molecules are arranged in a hexagonal honeycomb lattice.
Ultimately, a single layer of graphene is just one atom thick, which is flat enough to be considered a 2D material!
Future of Microphone Technology
The 60-layer thick graphene membrane used for the microphone was grown on a nickel foil with the help of a process called chemical vapour deposition. The base nickel foil is etched away and replaced with the graphene membrane to form a housing similar to those of commercial microphones. This allows for consistent quality across all samples used.
The research team also simulated creating a graphene membrane that’s 300 layers thick and has the potential for use in ultrasonics. Spasenovic adds that, “A thicker graphene membrane theoretically could be stretched further, enabling ultrasonic performance, but sadly we’re just not quite there yet experimentally.”