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Title: Cross-sectional transport imaging in a multijunction solar cell

Here, we combine a highly localized electron-beam point source excitation to generate excess free carriers with the spatial resolution of optical near-field imaging to map recombination in a cross-sectioned multijunction (Ga 0.5In 0.5P/GaIn 0.01As/Ge) solar cell. By mapping the spatial variations in emission of light for fixed generation (as opposed to traditional cathodoluminescence (CL), which maps integrated emission as a function of position of generation), it is possible to directly monitor the motion of carriers and photons. We observe carrier diffusion throughout the full width of the middle (GaInAs) cell, as well as luminescent coupling from point source excitation in the top cell GaInP to the middle cell. Supporting CL and near-field photoluminescence (PL) measurements demonstrate the excitation-dependent Fermi level splitting effects that influence cross-sectioned spectroscopy results, as well as transport limitations on the spatial resolution of conventional cross-sectional far-field measurements.
 [1] ;  [2] ;  [3] ;  [1] ;  [4] ;  [4]
  1. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  2. Naval Postgraduate School, Monterey, CA (United States)
  3. Nanonics Imaging Ltd., Jerusalem (Israel)
  4. Boeing Spectrolab, Sylmar, CA (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 2156-3381
Grant/Contract Number:
Accepted Manuscript
Journal Name:
IEEE Journal of Photovoltaics
Additional Journal Information:
Journal Volume: 7; Journal Issue: 1; Journal ID: ISSN 2156-3381
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE); NREL Laboratory Directed Research and Development (LDRD)
Country of Publication:
United States
14 SOLAR ENERGY; cathodoluminescence (CL); diffusion; luminescent coupling; multijunction solar cell; transport imaging
OSTI Identifier: