Researchers from the University of Utah have discovered that a special kind of perovskite can be layered on a silicon wafer to create a vital component for the communications system of the future. That system would use the terahertz spectrum, the next generation of communications bandwidth that uses light instead of electricity to move data.
By depositing a special form of multilayer perovskite onto a silicon wafer, then team can modulate terahertz waves passing through it using a simple halogen lamp. Modulating the amplitude of terahertz radiation is important because it is how data in such a communications system would be transmitted.
Previous attempts to do this have usually required the use of an expensive, high-power laser. What makes this demonstration different is that it is not only the lamp change but also the specific color of the light. Consequently, they can put different perovskites on the same silicon substrate, where each region could be controlled by different colors from the lamp. This is not easily possible when using conventional semiconductors like silicon.
“Think of it as the difference between something that is binary versus something that has 10 steps,” the team explains. “Silicon responds only to the power in the optical beam but not to the color. It gives you more capabilities to actually do something, say for information processing or whatever the case may be.”
Not only does this open the door to turning terahertz technologies into a reality, but the process of layering perovskites on silicon is simple and inexpensive by using a method called “spin casting,” in which the material is deposited on the silicon wafer by spinning the wafer and allowing centrifugal force to spread the perovskite evenly.
The researchers estimate it will be at least 10 more years before terahertz technology for communications and computing is used in commercial products, but this new research is a significant milestone to getting there.