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Title: Quantification of Sheet Resistance in Boron-Diffused Silicon Using Micro-Photoluminescence Spectroscopy at Room Temperature

A micro-photoluminescence-based technique is presented, to quantify and map sheet resistances of boron-diffused layers in silicon solar cell precursors with micron-scale spatial resolution at room temperature. The technique utilizes bandgap narrowing effects in the heavily-doped layers, yielding a broader photoluminescence spectrum at the long-wavelength side compared to the spectrum emitted from lightly doped silicon. By choosing an appropriate spectral range as a metric to assess the doping density, the impacts of photon reabsorption on the analysis can be avoided; thus, an accurate characterization of the sheet resistance can be made. This metric is demonstrated to be better representative of the sheet resistance than the surface doping density or the total dopant concentration of the diffused layer. The technique is applied to quantify sheet resistances of 12-um-wide diffused fingers in interdigitated back-contact solar cell precursors and large diffused areas. The results are confirmed by both 4-point probe and time-of-flight secondary-ion mass spectrometry measurements. Lastly, the practical limitations associated with extending the proposed technique into an imaging mode are presented and explained.
 [1] ;  [2] ;  [3] ;  [2] ;  [1] ;  [1] ;  [1] ;  [1] ;  [3] ;  [2] ;  [1]
  1. The Australian National Univ., Canberra, ACT (Australia)
  2. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  3. The Univ. of New South Wales, Sydney, NSW (Australia)
Publication Date:
Report Number(s):
Journal ID: ISSN 2367-198X
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Solar RRL
Additional Journal Information:
Journal Volume: 1; Journal Issue: 10; Journal ID: ISSN 2367-198X
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Country of Publication:
United States
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; diffusion; heavily doped silicon; photoluminescence; solar cells; spectroscopy
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1378116