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Heterostructural Semiconductor Alloys

Heterostructural Semiconductor Alloys

Wednesday, May 9, 2018 at 4:00 pm
304 Wngr
Andriy Zakutayev, National Renewable Energy Laboratory

Semiconductor alloys are routinely used to tune materials properties for optoelectronic energy conversion applications. Such solid solutions are usually derived from materials with the same crystal structure, for example zincblende (Al,Ga)As or wurtzite (Ga,In)N, forming isostructural semiconductor alloys. Heterostructural semiconductor alloys, on the other hand, are much less common. In this talk, I will present our recent insights into solid state physics and -chemistry of heterostructural semiconductor alloys. We found that such unusual alloys can access wide metastable regions of phase diagrams, leading to dramatic optoelectronic property changes in (Mn,Zn)O and (Sn,Ca)S. Surprisingly, heterostructural alloys can be also used to make polymorphs that are otherwise stable only under impractically large negative pressure, for example in Mn(Se,Te) or (Mn,Zn)Te. As a part of this talk, I will also describe high-throughput combinatorial experiments used to obtain these results, and show how they can be effectively coupled to first principles calculations.

Andriy Zakutayev is a staff scientist at the National Renewable Energy Laboratory in Golden, Colorado. He discovers new materials and devices for solar cells, Li-ion batteries, fuel cells, and other renewable energy technologies using materials-by-design methods coupled with high-throughput combinatorial synthesis. He obtained his PhD in Physics from Oregon State University in 2010.