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報 告 人：王禮國
指導老師：林克默 博士
日
期：2010.10.11.
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Outline
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1. Introduction
2. Experimental procedure
3. Results and discussion
4. Conclusions
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Introduction
• Considerable progress has been made in spatially resolved
solar cell characterization with camera-based techniques.
• Important cell and material parameters, such as recombination
lifetimes, trap densities, power losses, shunt distributions, or
diffusion lengths, can be imaged in a few minutes or
sometimes even seconds.
• We perform recombination current and series resistance
imaging on large-area crystalline silicon solar cells using a
combined analysis of camera-based dark lock-in thermography
DLIT and electroluminescence EL imaging.
• Combining the two images pixel by pixel allows us to
calculate images of the local recombination current and
thelocal series resistance of the solar cell.
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Experimental procedure
• The DLIT measurements are performed using an infrared
camera sensitive in the wavelength range from 3.9 to 5 m,
which is mounted in a dark chamber.11 A lock-in frequency
of 20 Hz is used for all images generated in this study,
which corresponds to a thermal diffusion length of 1.2 mm
in silicon.
• The EL setup uses a Si charge coupled device CCD camera
and is also mounted in a dark box.
• Correct the EL images for stray light and dark noise by
subtracting a dark image recorded at equal exposure time.
• During both measurements we connect the cells to a bipolar
power source and measure the current and voltage using a
four-point contacting scheme with 22 probes on each bus
bar.
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Results and discussion
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有四個重要的結論
一.光學效果忽略電阻與電流密度的兩種圖像，限制
量測均勻的晶片只能使用光學的量測方法，不均
勻的晶片需更正紅外線的發光與發射率。
二.他們假設DLIT忽略電流流過所產生的熱，這樣
的假設會使模組的電流上升1~3%。
三.假設外加電壓，這就使N結邊緣的空間電荷會超
過原本的電流密度與載子濃度，這樣就能忽略費
米能階的值，但在整個模組上是很微小的。
四.忽略銀膠的電阻，導致會低估總電阻值，值約
0.1 Ωcm2
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Conclusions
一.他們提出使用複合電流與串聯電組成像的方法，
再利用不同特徵技術，使相機擷取光與熱的訊號。
二.開創不損壞以及能夠快速檢測晶片特性的分析方
法；與接觸式的檢測法比較量測速度，只有非常
小的差異。
三.如果能夠結合光與熱訊號擷取技術，就能提高量
測電阻值的靈敏度。
四.如果考慮光的不均勻性，也能利用在檢測多晶矽
晶片。
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Thank you for your attention
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