John Mangum is a postdoctoral researcher in the High-Efficiency Crystalline Photovoltaics and Materials Discovery groups at NREL.

Part of his research focuses on epitaxial growth of III-V materials on nanopatterned and spalled substrates as a route towards integration of high-efficiency III-V devices on low-cost substrates. He also focuses on synthesis of ternary nitride thin films by combinatorial co-sputtering to develop novel photoanode materials used for photoelectrochemical CO2 reduction. He is specifically interested in crystalline defects that arise during epitaxial growth and characterizing them through a variety of techniques including electron channeling contrast imaging, X-ray diffraction, and transmission electron microscopy techniques.

For additional information, see John Mangum's LinkedIn profile

Disclaimer: Any opinions expressed on LinkedIn are the author’s own, made in the author's individual capacity, and do not necessarily reflect the views of NREL.

Research Interests

Defect formation mechanisms and growth behavior of III-V materials on nanopatterned and spalled substrates

Sputtering of novel ternary nitride thin films for photoelectrochemical applications

Crystalline defect characterization using electron microscopy (ECCI, TEM)

Education

Ph.D., Materials Science, Colorado School of Mines

B.S., Materials Science and Engineering, North Carolina State University

Associations and Memberships

Member, AVS

Member, Microscopy Society of America/Microanalysis Society

Member, IEEE

Featured Work

High-Efficiency Solar Cells Grown on Spalled Germanium for Substrate Reuse without Polishing, Advanced Energy Materials (2022)

Development of High-Efficiency GaAs Solar Cells Grown on Nanopatterned GaAs Substrates, Crystal Growth & Design (2021)

Using Electron Channeling Contrast Imaging to Inform and Improve the Growth of High-Efficiency GaAs Solar Cells on Nanopatterned GaAs Substrates, Journal of Crystal Growth (2021)

Utilizing TiO2 Amorphous Precursors for Polymorph Selection: An in situ TEM Study of Phase Formation and Kinetics, Journal of the American Ceramic Society (2020)

Selective Brookite Polymorph Formation Related to the Amorphous Precursor State in TiO2 Thin Films, Journal of Non-Crystalline Solids (2019)

Correlative Raman Spectroscopy and Focused Ion Beam for Targeted Phase Boundary Analysis of Titania Polymorphs, Ultramicroscopy (2018)