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報 告 人：王禮國
指導老師：林克默 博士
日
期：2010.11.22.
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• Edge recombination can have a significant impact on the
performance of small-area, high-efficiency silicon solar cells.
Photoluminescence characterization techniques are applied to
assess isolation trench techniques that are designed to remove
edge recombination from such solar cells, thereby improving
performance and allowing the true bulk properties of the solar
cell to be evaluated independent of edge effects.
• This letter uses photoluminescence PL techniques to assess the
suitability of a trench isolation method to mitigate edge
recombination in small.
• Photoluminescence mapping of silicon wafers has been
applied in the past, e.g., to assess spatial variations of the
material quality, to correlate such variations with dislocation
densities, or to determine diffusion length maps.
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• Suns-photoluminescence Suns-PL and
photoluminescence imaging which have
recently been described.
• Similar to photoconductance and infrared free
carrier absorption,PL is contactless and can be
used for partially finished devices.
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• All samples were fabricated on 1Ω cm n-type float
zoned silicon. The front surface was diffused with
boron 100 / to create an emitter. The rear surface was
diffused with phosphorous 100 / to create a high-low
junction. A 350 nm thick thermal oxide was grown on
both sides for surface passivation. On one sample, a
laser was used to scribe an isolation trench through
the boron emitter. The trench was cut in a square
pattern with dimensions of 2.8 cm2.8 cm. The trench
was etched with a weak NaOH etch to remove laser
damage and residual ablation slag. After etching the
isolation trench was passivated with a phosphorous
diffusion 100 / and thermal oxide 350 nm.
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• After fabrication, the injection-level-dependent
effective minority-carrier lifetimes of the
samples were characterized using QSS-PL.
• All measurements were made on a 2X2 cm2
active area in the center of the samples; on
the relevant sample, this area was completely
within the isolation trench.
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•
•
光致發光特性技術已被用於研究晶片溝槽技術，
減少邊緣複合和P-N接面相接短路效果。
非接觸式檢測技術，可用於分析部分已完成太陽
能電池(製程時的任意過程)皆可檢測，相較須完
成太陽能電池製作的檢測技術設備，減少了時間
與成本，具很大優勢，而且可避免而外處理可能
引入的不確定性的檢測。
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Thank you for your attention
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