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Welcome to the Santala Research Group!

We use transmission electron microscopy, including aberration-corrected (S)TEM and photo-emission TEM, and other characterization techniques to study:

  • the role surfaces and interfaces in the structural and phase stability of materials
  • kinetics of phase transformations, including swtiching of chalcogenide-based phase change materials
Structural characterization of metal/γ-alumina interfaces

The objective of this NSF project, entitled “Atomic-level structural characterization of metal/γ-alumina interfaces combining theory and experiments,” is to create excellent overlap between the experimental structural characterization of metal/γ-alumina interfaces and density functional theory (DFT) based calculations, and to connect the structural information to the thermodynamic properties in the interface, including the interfacial free energy. The proposal is co-authored and is in collaboration with Dr. Líney Árnadóttír. Proposed work will be achieved using ion implantation followed by thermal annealing to produce well-defined, model metal/γ-alumina interfaces with catalytically important metal species enabling atomic resolution imaging of both phases simultaneously. The project will utilize aberration-corrected TEM and scanning TEM (STEM) to produce high quality quantitative structural data regarding the relative position of all chemical species (Al, O, and the metal) that can be meaningfully compared to DFT-based calculations of the structure and thermodynamic stability ranges of interfaces with different γ-alumina chemical terminations.

Above: Platinum nanoparticles in Θ-alumina. Taken with the TEAM 0.5 at the National Center for Electron Microscopy


Crystallization kinetics of amorphous semiconductors and phase change materials

Santala Research Group GE

Above: False color image of amorphous Ge (purple) crystallizing after laser heating. The crystalline front progagates at approximately 10 m/s. Imaged with the Dynamic TEM at Lawrence Livermore National Laboratory.