John Michael Yarbrough

John Michael Yarbrough

Research Scientist

Photo of John Michael Yarbrough
(303) 384-6831
At NREL Since: 

John Yarbrough received his Ph.D. in Applied Physics from the Colorado School of Mines in 2007 where his research activities primarily involved investigating the electronic and optical properties of advanced polycrystalline semiconductor materials systems and device structures. He spent most of his time at CSM developing and using novel characterization techniques to obtain a fundamental understanding of these advanced semiconductor materials.

During his time at CSM, Dr. Yarbrough was involved in studying the overall effects that grain boundaries have on the performance of thin-film polycrystalline photovoltaic devices. This research involved designing and building of a vacuum compatible near-field scanning optical microscope (NSOM) to optically and electrically characterize these advanced semiconductor materials. The NSOM was used to perform both near-field spatial and spectral photoluminescence and near-field spatial photocurrent measurements on a submicron level scale on both CdTe and CIGS thin-film polycrystalline photovoltaic devices.

Dr. Yarbrough's research interest is in the development and implementation of novel characterization techniques in the area of imaging and spectroscopy to obtain a better fundamental understanding of biological systems and the process of biomass conversion, on a nanometer/micron-level scale, which is used in the area of alternative and renewable energies.


  • 2007, Ph.D., Applied Physics, Colorado School of Mines

  • 2003, M.S., Physics, University of Texas at Arlington

  • 2000, B.S., Physics, University of Texas at Arlington

Selected Publications 

  1. Yarbrough, J.M.; Collins, R.T.; Beach, J.D.; Egaas, B.; Kaydanov, V.; Ohno, T.R. (October 2004). "Multiple Wavelength Near Field Scanning Optical Microscopy Study of Thin Film Polycrystalline Solar Cells." Proceedings of the DOE Solar Program Review Meeting 2004; Denver, CO: pp. 127-128.
  2. Schick, I.C.; Yarbrough, J.M.; Allen, C.G.; Collins, R.T. (2006). "Novel method to compensate for fluctuations in optical power delivered to an NSOM." Review of Scientific Instruments (44); p. 66.
  3. Schick, I.C.; Flammer, P.D.; Yarbrough, J.M.; Allen, C.G.; Nuebel, G.; Schick, E.J.; Dahdah, J.M.;; Martineau, J.T.; Hurowitz, M.A.; Hollinsgworth, R.E.; Collins, R.T. (2006). "Experimental study of enhanced transmission through sub-wavelength linear apertures flanked by periodic corrugations." Proc. SPIE (6323); p. 6323OL.
  4. Bera, S.; A. Sabbah,J.; Yarbrough, J.M.; Allen, C.G.; Winters, B.; Durfee, C.G.; Squier, J.A. (2007). "Optimization of Laser Induced Forward Transfer (LIFT) process in aluminum." Applied Optics (46:21);