Scientists develop aluminium & aluminium oxide nanocavity that improves semiconductor light absorption

Researchers from the University at Buffalo have developed a method of making ultrathin semiconducting materials using aluminium oxide (Al2SO4) and aluminium.

According to researchers, laying a layer of molybdenum disulfide (MoS2) molecules atop an optical nanocavity made from aluminium oxide and aluminium can increase the amount of light the semiconducting material is able to absorb. A nanocavity is a mirror structure that routes light in a closed circuit. Nanocavities are key to assembling lasers and fiber optics, among other light applications.

“The nanocavity we have developed has many potential applications,” explained University at Buffalo’s School of Engineering and Applied Sciences assistant professor of electrical engineering Qiaoqiang Gan, Ph.D. “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.”

In order to stay ahead of the race to make electronic devices ever smaller, industry has made smaller and smaller semiconductors for use in constructing optoelectronic devices. However, this has become more and more problematic due to the fact that ultrathin semiconductors do not absorb light as readily as standard semiconductors. The thinner the semiconductor, the worse the absorption capacity becomes.

The single layer of molybdenum disulfide is desirable because the material’s bandgap is similar to semiconductors that are currently used in LED’s, lasers, and solar cells, solving the problem of the trade-off between semiconductor thickness and light absorption. This is a distinct advantage over graphene, which is also being considered for similar applications.

“In experiments, the nanocavity was able to absorb nearly 70 percent of the laser we 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 co-lead researcher Haomin Song, a Ph.D. candidate.