John Mangum is a postdoctoral researcher in the high-efficiency crystalline photovoltaics group at NREL. His research focuses on homoepitaxial growth of III-V materials on nano-patterned substrates as a route towards integration of high-efficiency III-V devices on low-cost substrates. He is specifically interested in coalescence-related defects that arise during growth on patterned substrates and characterizing them through a variety of techniques including electron channeling contrast imaging, photoluminescence spectroscopy, and X-ray diffraction.

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Research Interests

Growth behavior and coalescence of III-V materials on nano-patterned substrates

Semiconductor defect characterization

Electron channeling contrast imaging


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

Featured Work

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)