Nano-XRF Analysis of Metal Impurities Distribution at PL Active Grain Boundaries during mc-Silicon Solar Cell Processing

Simone Bernardini, Steve Johnston, Bradley West, Tine U. Naerland, Michael Stuckelberger, Barry Lai, Mariana Bertoni

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

Metal impurities are known to hinder the performance of commercial Si-based solar cells by inducing bulk recombination, increasing leakage current, and causing direct shunting. Recently, a set of photoluminescence (PL) images of neighboring multicrystalline silicon wafers taken from a cell production line at different processing stages has been acquired. Both band-To-band PL and sub-bandgap PL (subPL) images showed various regions with different PL signal intensity. Interestingly, in several of these regions a reversal of the subPL intensity was observed right after the deposition of the antireflective coating. In this paper, we present the results of the synchrotron-based nano-X-ray fluorescence imaging performed in areas characterized by the subPL reversal to evaluate the possible role of metal decoration in this uncommon behavior. Furthermore, the acquisition of a statistically meaningful set of data for samples taken at different stages of the solar cell manufacturing allows us to shine a light on the precipitation and rediffusion mechanisms of metal impurities at these grain boundaries.

Original languageEnglish (US)
Article number7742961
Pages (from-to)244-249
Number of pages6
JournalIEEE Journal of Photovoltaics
Volume7
Issue number1
DOIs
StatePublished - Jan 1 2017

Keywords

  • Multicrystalline silicon (mc-Si)
  • photoluminescence (PL)
  • PL band reversal sub-band PL
  • X-ray fluorescence

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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