What remained was a freestanding ultrathin sheet of semiconducting material.Įom, an expert in complex oxide materials, says they are intriguing because they have a wide range of tunable properties - including multiple properties in one material - that many other materials do not.
The researchers could remove the semiconductor layer from the graphene. Just one molecule thick, the graphene acts like a peel-away backing due to its weak bonding. Led by Jeehwan Kim, an associate professor in mechanical engineering and materials science and engineering at MIT, the group added an ultrathin intermediate layer of a unique carbon material called graphene, then used epitaxy to grow a thin semiconducting material layer atop that. That's a constraint, and beyond that constraint, it doesn't grow well."Ī couple of years ago, a team of MIT researchers developed an alternate approach. "When you grow the next material, your structure has to be the same and your atomic spacing must be similar. "The advantage of the conventional method is that you can grow a perfect single crystal on top of a substrate, but you have a limitation," says Chang-Beom Eom, a UW-Madison professor of materials science and engineering and physics. If there's a mismatch, the blocks won't fit together properly. It's sort of like stacking Lego blocks: The holes on the bottom of one block must align with the raised dots atop the other. The researchers' new layering method overcomes a major challenge in conventional epitaxy - that each new complex oxide layer must be closely compatible with the atomic structure of the underlying layer. 5 in the journal Nature.Įpitaxy is the process for depositing one material on top of another in an orderly way.
The team published details of its advance Feb. Now, using a new platform developed by engineers at the University of Wisconsin-Madison and the Massachusetts Institute of Technology, researchers will be able to make these stacked-crystal materials in virtually unlimited combinations.
Stacking ultrathin complex oxide single-crystal layers - those composed of geometrically arranged atoms - allows researchers to create new structures with hybrid properties and multiple functions.
0 kommentar(er)
