Helio Moutinho

Senior Scientist


Helio Moutinho is a senior scientist with the Analytical Microscopy Group. The group is involved in investigating structural and electro-optical properties using scanning and transmission electron microscopy and scanning probe microscopy of most semiconductor materials and devices used in solar cell research, such as CdTe, CIGS, Si, III-Vs, and perovskite. Helio has extensive experience in several characterization techniques, including scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), atomic force microscopy (AFM), scanning Kelvin probe microscopy (SKPM), conductive atomic force microscopy (C-AFM), scanning capacitance microscopy (SCM), and X-ray diffraction (XRD). He is involved in developing near-field transport imaging at NREL to study the transport of charge carriers in semiconductors with high spatial resolution.

Research Interests

  • Studying the influence of different growth and processing parameters on the development of the microstructure and electro-optical properties of solar cell materials and devices—in particular, CdTe devices with different structures and subject to different treatments.
  • Developing near-field transport imaging applied to solar cell materials and devices, including the determination of diffusion length in single grains and the effect of grain boundaries in CdTe, and the effects of defects on the transport properties of III-V materials.
  • Investigating the interaction mechanisms between dust particles and solar glass responsible for soiling in solar panels, such as van der Waals and capillary forces, using measurements such as AFM force vs distance curves, scanning electron microscopy, and energy-dispersive X-ray spectroscopy.
  • Correlating between macroscopic and microscopic properties in photovoltaic modules, including the development of coring procedures for extracting small samples from modules without introducing damage or changing the material properties.


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

M.S. Materials Science, Military Institute of Engineering, Rio de Janeiro, Brazil 

B.S. Physics, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil 

Featured Work

  • C. Xiao, C.-S. Jiang, H.R. Moutinho, D. Levi, Y. Yan, B. Gorman, and M.M. Al-Jassim, Locating the electrical junction in Cu(In,Ga)Se2 and Cu2ZnSnSe4 solar cells by scanning capacitance spectroscopy, Progress in Photovoltaics: Research and Applications 2016, DOI: 10.1002/pip.2805
  • H.R. Moutinho, R.G. Dhere, C.-S. Jiang, Y. Yan, D.S. Albin, and M.M. Al-Jassim, Investigation of potential and electric field profiles in cross sections of CdTe/CdS solar cells using scanning Kelvin probe microscopy, J. Appl. Phys. 108, 074503 (2010).
  • H.R. Moutinho, R.G. Dhere, M.J. Romero, C.-S. Jiang, B. To, and M.M. Al-Jassim, Electron backscatter diffraction of CdTe thin films: Effects of CdCl2 treatment, J. Vac. Sci. Technol. A 26, 1068 (2008).
  • H.R. Moutinho, R.G. Dhere, C.-S. Jiang, T. Gessert, A. Duda, M. Young, W.K. Metzger, and M.M. Al-Jassim, The role of Cu on the electrical properties of CdTe/CdS solar cells—A cross-sectional conductive atomic force microscopy study. J. Vac. Sci. Technol. B 25, 361 (2007).

View all NREL publications for Helio Moutinho.