Researchers from the Royal Melbourne Institute of Technology (RMIT) are looking to shake up the world of electronics, both literally and figuratively. The key to harnessing the power of 2D materials is so-called “nano-earthquakes,” according to Dr. Sumeet Walia and Dr. Amgad Rezk. They’ve found that sound waves, properly controlled, can affect the electronic properties of 2D materials like graphene.

The earthquake language isn’t referring to anything related to real earthquakes, but the way surface acoustic waves (SAWs) can propagate through a material. This experiment used a quasi-2D material known molybdenum disulfide that can act as a semiconductor similar to silicon. In this case it was used as a source of photoluminescence. A layer several atoms thick was coupled to a substrate, so the researchers could study what happens when SAWs ripple across the surface.

Both the direction and intensity of the ripples could be controlled in this experiment, allowing the team to modulate the electronic properties of the 2D material. The research pointed to a tight relationship between the nano-quakes and the electronic performance of the molybdenum disulfide layer. As the intensity of the nano-quakes increased, so too did the photoluminescence of the 2D material. More acoustic ripples resulted in more light being emitted by the layer.

It is believed that the sound waves act like a carrier for electrons, dragging them along the surface as they propagate. This is what changes the electronic properties of the material. It basically increases electrical conductance, but only while the system is active.

The researchers see a number of uses for this technology in the future use of 2D materials, especially when it comes to optoelectronic applications. For example, smartphone cameras are often hampered in low light by their small sensor size, but a sensor made with a 2D material could increase sensitivity in these situations through the use of sound waves in the camera module. Solar panels could also be improved through the manipulation of 2D materials with sound.

According to the RMIT team, this technique is very robust thanks to the desirability of 2D materials. As soon as the acoustic vibrations were halted in the study, the molybdenum disulfide layer returned to its original electronic state and suffered no physical damage. This sort of fine-tuning is one of the missing pieces for 2D materials as semiconductors. The same techniques should work on graphene and similar substances.