Wurtzite ferroelectrics suggest a pathway to high-temperature memory. However, their lifetime doesn’t quite yet meet targets. Walter’s work shows that a limiting factor is the formation of N-vacancies that occurs as the materials switch.

Oxygen vacancies help stabilize the ferroelectric phase in Hafnium-Zirconium-Oxide (HZO). They also lead to leakage that eventually limits this promising memory material. We should know where they live in energy space. In work with Sandia National Labs, Fernando leveraged photoexcited electron emission spectroscopy (PEEM) to identify the band of defects that exist about 1 eV below the conduction band in HZO.

He took home the best paper award for his work tracking defect evolution in wurtzite ferroelectrics. Extremely proud of his dogged determination on this project.