Optical Evaluation of Silicon Wafers With Rounded Rear Pyramids
| Autor: | Kean Chern Fong, Ngwe Zin, Teng Kho, Er-Chien Wang, Teck K. Chong, T. Ratcliff, Keith R. McIntosh, Evan Franklin, Matthew Stocks, Hieu T. Nguyen, Daniel Macdonald, Andrew Blakers |
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| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Photoluminescence Materials science Passivation Silicon business.industry chemistry.chemical_element 02 engineering and technology Surface finish 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Electronic Optical and Magnetic Materials Wavelength Optics chemistry 0103 physical sciences Wafer Texture (crystalline) Electrical and Electronic Engineering 0210 nano-technology business Absorption (electromagnetic radiation) |
| Zdroj: | IEEE Journal of Photovoltaics. 7:1596-1602 |
| ISSN: | 2156-3403 2156-3381 |
| DOI: | 10.1109/jphotov.2017.2754060 |
| Popis: | We investigate the light trapping in Si wafers that are textured with conventional random pyramids on their front surface and rounded random pyramids on their rear. It is well established that rounding the pyramids leads to better surface passivation, but whether or not it improves light trapping depends on the cell structure. In this paper, we apply ray tracing, spectrophotometry, and photoluminescence spectroscopy (PLS) to understand and quantify how rounding the rear pyramids might affect the light trapping in back-contact solar cells. We describe how rounding the pyramids leads to two competing optical effects: 1) reduced absorption in the rear films and 2) reduced scattering from the rear texture. The first effect improves light trapping whereas the latter degrades it. We show how the influence of each effect depends on wavelength and how they can be discerned (but not easily quantified) in reflectance curves. With PLS measurements, we conclude that for our sample structure and etch solution, the generation current is approximately constant for etch durations less than ∼60 s, and decreases significantly as the etch duration increases. Thus, by limiting the duration of the rounding etch, superior surface passivation can be attained without degrading the light trapping. |
| Databáze: | OpenAIRE |
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