As optoelectronic devices become smaller and thinner, a problem has developed where they do not absorb light as well as conventional bulk semiconductors, limiting their usefulness. A team of American electrical engineers may have come up with a solution using molybdenum disulfide (MOS2) and nanocavities.
The team from the University of Buffalo in New York State found the MoS2 nanocavity can increase the amount of light that ultrathin semiconducting materials absorb. In turn, this could help industry to continue manufacturing more powerful, efficient and flexible electronic devices.
A nanocavity is an arrangement of mirrors that allows beams of light to circulate in closed paths and are used to build things like lasers and optical fibres for communications. The Buffalo team used an optical nanocavity made of aluminum oxide and aluminum with a single layer of MoS2 molecules placed on top.
“The nanocavity we have developed has many potential applications,” said Electrical Engineering Assistant Professor Qiaoqiang Gan.
“It could potentially be used to create more efficient and flexible solar panels, and faster photodetectors for video cameras and other devices. It may even be used to produce hydrogen fuel through water splitting more efficiently.”
He said a single layer of MoS2 is advantageous because unlike another promising two-dimensional material, graphene, its bandgap structure is similar to semiconductors used in LEDs, lasers and solar cells.
The team's experiments found the nanocavity was able to absorb nearly 70 percent of the laser projected on it.
"Its ability to absorb light and convert that light into available energy could ultimately help industry continue to more energy-efficient electronic devices,” said Haomin Song, one of the researchers in the team.
Their research is described in the paper “MoS2 monolayers on nanocavities: enhancement in light-matter interaction” published in the journal 2D Materials.
An optical nanocavity made, from top to bottom, of molybdenum disulfide (MoS2), aluminum oxide and aluminum. Image: University of Buffalo