John Mangum is a materials science researcher in the Analytical Microscopy and Imaging Science and Materials Discovery groups at NREL. His research focuses on using advanced microscopy and spectroscopy techniques to study energy-relevant materials, ranging from fundamental atomic-scale mechanisms to macroscale degradation and durability of industrial technologies. He also studies the synthesis of ternary nitride thin films by combinatorial cosputtering to develop novel photoelectrode materials for photoelectrochemical CO₂ reduction. He is specifically interested in crystalline defects and strain 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.

Research Interests

Multiscale microscopy (and spectroscopy) techniques for characterizing nanoscale mechanisms that drive macroscale behaviors

Crystalline defect characterization using electron microscopy (electron channeling contrast imaging, transmission electron microscopy)

Sputtering synthesis of novel ternary nitride thin films for photoelectrochemical applications

Education

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

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

Professional Experience

Physical Sciences Representative, Mountain States Society of Electron Microscopists (2022–Present)

Sunrise Network Leadership Team Member, Liquid Sunlight Alliance (2021–2022)

Conference Organizer, Colorado Center for Advanced Ceramics (2017–2018)

Associations and Memberships

Member, Mountain States Society of Electron Microscopists

Member, Microscopy Society of America/Microanalysis Society

Featured Work

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)

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

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)

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

Patents

Patterned Nanochannel Sacrificial Layer for Semiconductor Substrate Reuse, U.S. Patent No. 20220310389 (2022)

Awards and Honors

Microscopy Society of America–Travel Award for IMC19 (2018)

Microanalysis Society–Goldstein Award (2016)