Creating A New Family Of Semiconductors

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Researchers create high-quality thin films of a new family of semiconductor materials that could have applications in solar cells and lighting.

The ability to create thin films of semiconductor materials led to computers, solar cells, night-vision cameras, and more. Now, researchers from MIT have created high-quality thin films of a new family of semiconductor materials. This new family of semiconductors is known as chalcogenide perovskites. 

Jaramillo, the Thomas Lord Associate Professor of Materials Science and Engineering at MIT says that “the history of semiconductor research shows that new families of semiconductors are generally enabling in ways that are not predictable.”

The thin films are composed of barium, zirconium, and sulfur in a specific crystal structure. Jaramillo says, “”You can make variations by changing the composition. So it is indeed a family of materials, not just a one-off.”

Jaramillo and team used molecular beam epitaxy (MBE) technique to grow their high-quality films. This technique allows for atomic level growth. In this technique, beams of molecules are pointed at a specific arrangement of atoms on a surface. That arrangement of atoms provides a template for the beamed molecules to grow on. “That’s why epitaxial growth gives you the highest-quality films. The materials know how to grow,” Jaramillo says.

However, according to Jaramillo, the chemicals needed to make chalcogenides are nasty. They stink, and they can gum up equipment. 

Says Hideo Hosono, a professor at the Tokyo Institute of Technology who was not involved in the work, “the thin films [created by Jaramillo et al.] show a mirror-smooth image as a result of an atomically flat surface and excellent quality. We may anticipate the realization of device fabrication such as solar cells and green LEDs as the next publications.”

“It’s almost a question of what isn’t next,” Jaramillo says. “Now that we can make these high-quality materials, there’s almost no measurement we could do that wouldn’t be interesting to a wide community of people.” For now, his group is focusing on two areas: exploring fundamental questions to gain a better understanding of the materials, and integrating them into solar cells. In one of his postdoctoral appointments before joining the MIT faculty, Jaramillo worked on solar cells, so “I’ll be able to leverage a lot of what I did then.”

The research appeared in the journal Advanced Functional Materials.


 

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