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Title: Quality Characterization of Silicon Bricks using Photoluminescence Imaging and Photoconductive Decay: Preprint

Imaging techniques can be applied to multicrystalline silicon solar cells throughout the production process, which includes as early as when the bricks are cut from the cast ingot. Photoluminescence (PL) imaging of the band-to-band radiative recombination is used to characterize silicon quality and defects regions within the brick. PL images of the brick surfaces are compared to minority-carrier lifetimes measured by resonant-coupled photoconductive decay (RCPCD). Photoluminescence images on silicon bricks can be correlated to lifetime measured by photoconductive decay and could be used for high-resolution characterization of material before wafers are cut. The RCPCD technique has shown the longest lifetimes of any of the lifetime measurement techniques we have applied to the bricks. RCPCD benefits from the low-frequency and long-excitation wavelengths used. In addition, RCPCD is a transient technique that directly monitors the decay rate of photoconductivity and does not rely on models or calculations for lifetime. The measured lifetimes over brick surfaces have shown strong correlations to the PL image intensities; therefore, this correlation could then be used to transform the PL image into a high-resolution lifetime map.
Authors:
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Publication Date:
OSTI Identifier:
1051905
Report Number(s):
NREL/CP-5200-54115
DOE Contract Number:
AC36-08GO28308
Resource Type:
Conference
Resource Relation:
Conference: Presented at the 2012 IEEE Photovoltaic Specialists Conference, 3-8 June 2012, Austin, Texas
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy Solar Energy Technologies Program
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; PHOTOLUMINESCENCE; IMAGING; INFRARED IMAGING; CHARGE-CARRIER LIFETIME; PHOTOCONDUCTIVITY; PHOTOVOLTAIC CELLS; SILICON; IMPURITIES; Solar Energy - Photovoltaics