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.
Currently, his two main research areas are: (1) developing foundational knowledge for the design, characterization and measurement of three-terminal solar cells and voltage-matched strings; and (2) using a fundamental understanding of dislocation formation in coalescing materials to direct projects investigating III-V growth on inexpensive and reusable substrates.
Ph.D., Physics, University of Illinois, Urbana-Champaign
M.S., Physics, University of Illinois, Urbana-Champaign
B.S., Engineering Physics, Colorado School of Mines
A Taxonomy for Three-Terminal Tandem Solar Cells, ACS Energy Letters (2020)
High-Temperature Nucleation of GaP on V-Grooved Si, Crystal Growth & Design (2020)
Control of Misfit Dislocation Glide Plane Distribution during Strain Relaxation of CuPt-Ordered GaInAs and GaInP, Journal of Applied Physics (2012)
Ordering-Enhanced Dislocation Glide in III-V Alloys, Journal of Applied Physics (2013)
Fill Factor as a Probe of Current-Matching for GaInP2/GaAs Tandem Cells in a Concentrator System during Outdoor Operation, Progress in Photovoltaics: Research and Applications (2008)
Strain-Driven Mesoscopic Reconstruction of the As/Ge(111) Surface, Physical Review Letters (2002)
Steps on As-Terminated Ge(001) Revisited: Theory versus Experiment, Physical Review Letters (2001)
5-7-5 Line Defects on As/Si(100): A general Stress-Relief Mechanism for V/IV Surfaces, Physical Review (2006)
View all NREL publications for Bill McMahon.