Biography
Bill McMahon has conducted research at NREL for more than 25 years. During this time, he has performed foundational research on a wide range of topics impacting the growth, fabrication, and performance of high-efficiency III‑V solar cells. As a postdoctoral researcher, he studied the atomic structure of MOCVD-prepared semiconductor surfaces used in III‑V growth on silicon and germanium surfaces. His research into the atomic structure of dislocations explained how ordering of III-V alloys can increase the glide force on dislocations, impacting the growth of lattice-mismatched solar cells. He has also led investigations into cell bonding, nano-imprinted optical coatings, distributed resistance modeling of 3-D current flow in multijunction solar cells, and energy-yield measurement and modeling.
Research
Developing foundational knowledge for the design, characterization and measurement of three-terminal solar cells and voltage-matched strings
Using a fundamental understanding of dislocation formation in coalescing materials to direct projects investigating III-V growth on inexpensive and reusable substrates
Publications
Lorelle M. Mansfield, Jacob J. Cordell, Sirazul Haque, William E. McMahon, Emily L. Warren
Your Best Single-Junction Solar Cell Does Not Always Make an Efficient Tandem Partner
ACS Energy Letters 10
(2024)
Gavin P. Forcade, William E. McMahon, Nicholas Yoo, Anica N. Neumann, Michelle Young, John Goldsmith, Sarah Collins, Karin Hinzer, Corinne E. Packard, Myles A. Steiner
Planarizing Spalled GaAs(100) Surfaces by MOVPE Growth
Crystal Growth & Design 24
(2024)
Imran S. Khan, William E. McMahon, Chun-Sheng Jiang, Patrick Walker, Andriy Zakutayev, Andrew G. Norman
Pulsed Laser Deposition of Epitaxial SrTiO3/Sr3Al2O6 Templates as a Water-Soluble Sacrificial Layer for GaAs Growth and Lift-Off
Crystal Growth & Design 24
(2024)
William E. McMahon, Anna K. Braun, Allison N. Perna, Pablo G. Coll, Kevin L. Schulte, Jacob T. Boyer, Anica N. Neumann, John F. Geisz, Emily L. Warren, Aaron J. Ptak, Arno P. Merkle, Mariana I. Bertoni, Corinne E. Packard, Myles A. Steiner
In Situ Smoothing of Facets on Spalled GaAs(100) Substrates during OMVPE Growth of III–V Epilayers, Solar Cells, and Other Devices: The Impact of Surface Impurities/Dopants
Crystal Growth & Design 24
(2024)
Kevin L. Schulte, Steve W. Johnston, Anna K. Braun, Jacob T. Boyer, Anica N. Neumann, William E. McMahon, Michelle Young, Pablo Guimerá Coll, Mariana I. Bertoni, Emily L. Warren, Myles A. Steiner
GaAs solar cells grown on acoustically spalled GaAs substrates with 27% efficiency
Joule 7
(2023)
Theresa E. Saenz, John S. Mangum, Olivia D. Schneble, Anica N. Neumann, Ryan M. France, William E. McMahon, Jeramy D. Zimmerman, Emily L. Warren
Coalescence of GaP on V-Groove Si Substrates
ACS Applied Electronic Materials 5
(2023)
William E. McMahon, John F. Geisz, Jeronimo Buencuerpo, Emily L. Warren
A framework for comparing the energy production of photovoltaic modules using 2-, 3-, and 4-terminal tandem cells
Sustainable Energy & Fuels 7
(2023)
Kaitlyn T. VanSant, Emily L. Warren, John F. Geisz, Talysa R. Klein, Steve Johnston, William E. McMahon, Henning Schulte-Huxel, Michael Rienäcker, Robby Peibst, Adele C. Tamboli
A performance comparison between GaInP-on-Si and GaAs-on-Si 3-terminal tandem solar cells
iScience 25
(2022)
John S. Mangum, San Theingi, Anica N. Neumann, William E. McMahon, Emily L. Warren
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 581
(2022)
Anna K. Braun, San Theingi, William E. McMahon, Aaron J. Ptak, Corinne E. Packard
Controlled spalling of (100)-oriented GaAs with a nanoimprint lithography interlayer for thin-film layer transfer without facet formation
Thin Solid Films 742
(2022)
John F. Geisz, William E. McMahon, Jeronimo Buencuerpo, Michelle S. Young, Michael Rienäcker, Adele C. Tamboli, Emily L. Warren
Characterization of multiterminal tandem photovoltaic devices and their subcell coupling
Cell Reports Physical Science 2
(2021)
John S. Mangum, San Theingi, Myles A. Steiner, William E. McMahon, Emily L. Warren
Development of High-Efficiency GaAs Solar Cells Grown on Nanopatterned GaAs Substrates
Crystal Growth & Design 21
(2021)
William McMahon, Henning Schulte-Huxel, Jeronimo Buencuerpo, John Geisz, Michelle Young, Talysa Klein, Adele Tamboli, Emily Warren
Homogenous Voltage-Matched Strings Using Three-Terminal Tandem Solar Cells: Fundamentals and End Losses
IEEE Journal of Photovoltaics 11
(2021)
Theresa E. Saenz, William E. McMahon, Andrew G. Norman, Craig L. Perkins, Jeramy D. Zimmerman, Emily L. Warren
High-Temperature Nucleation of GaP on V-Grooved Si
Crystal Growth & Design 20
(2020)
William E. McMahon, Michelle Vaisman, Jeramy D. Zimmerman, Adele C. Tamboli, Emily L. Warren
Perspective: Fundamentals of coalescence-related dislocations, applied to selective-area growth and other epitaxial films
APL Materials 6
(2018)
Michelle Vaisman, Nikhil Jain, Qiang Li, Kei May Lau, Emily Makoutz, Theresa Saenz, Willian E. McMahon, Adele C. Tamboli, Emily L. Warren
GaAs Solar Cells on Nanopatterned Si Substrates
IEEE Journal of Photovoltaics 8
(2018)
John F. Geisz, Myles A. Steiner, Nikhil Jain, Kevin L. Schulte, Ryan M. France, William E. McMahon, Emmett E. Perl, Daniel J. Friedman
Building a Six-Junction Inverted Metamorphic Concentrator Solar Cell
IEEE Journal of Photovoltaics 8
(2018)
Iván Garcia, William E. McMahon, Aron Habte, John F. Geisz, Myles A. Steiner, Manajit Sengupta, Daniel J. Friedman
Spectral binning for energy production calculations and multijunction solar cell design
Progress in Photovoltaics: Research and Applications 26
(2017)
William E. McMahon, Daniel J. Friedman, John F. Geisz
Multijunction solar cell design revisited: disruption of current matching by atmospheric absorption bands
Progress in Photovoltaics: Research and Applications 25
(2017)
Emily L. Warren, Alan E. Kibbler, Ryan M. France, Andrew G. Norman, Paul Stradins, William E. McMahon
Growth of antiphase-domain-free GaP on Si substrates by metalorganic chemical vapor deposition using an in situ AsH3 surface preparation
Applied Physics Letters 107
(2015)
William E. McMahon, Joongoo Kang, Ryan M. France, Andrew G. Norman, Daniel J. Friedman, Su-Huai Wei
Ordering-enhanced dislocation glide in III-V alloys
Journal of Applied Physics 114
(2013)
W.E. McMahon, A.E. Kibbler, J.M. Olson
An STM and LEED study of MOCVD-prepared P/Ge (1 0 0) to (1 1 1) surfaces
Surface Science 571
(2004)
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