《报告指导博士》PPT课件.ppt

,1,Outline,1. Introduction 2. Experimental procedure 3. Results and discussion 4. Conclusions,2,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.,3,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.,4,Results and discussion,5,6,有四個重要的結論 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。 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13%。 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。 忽略銀膠的電阻，導致會低估總電阻值，值約0.1 cm2,7,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。 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。 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。 如果考慮光的不均勻性，也能利用在檢測多晶矽晶片。,8,Conclusions,Thank you for your attention,9,