Rie-texturing of multicrystalline silicon solar cells (original) (raw)
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Plasma-texturization for multicrystalline silicon solar cells
Conference Record of the Twenty-Eighth IEEE Photovoltaic Specialists Conference - 2000 (Cat. No.00CH37036), 2000
Multicrystalline Si (mc-Si) cells have not benefited from the cost-effective wet-chemical texturing processes that reduce front surface reflectance on single-crystal wafers. We developed a maskless plasma texturing technique for mc-Si cells using Reactive Ion Etching (RIE) that results in much higher cell performance than that of standard untextured cells. Elimination of plasma damage has been achieved while reducing front reflectance to extremely low levels. Internal quantum efficiencies higher than those on planar and wet-textured cells have been obtained, boosting cell currents and efficiencies by up to 11% on monocrystalline Si and 2.5% on multicrystalline Si cells.
Large-area multicrystalline silicon solar cell fabrication using reactive ion etching (RIE)
Solar Energy Materials and Solar Cells, 2011
Surface texturing of crystalline silicon wafer improves the conversion efficiency of solar cells by the enhancement in antireflection property and light trapping. Compared to antireflection coating, it is a more permanent and effective scheme. Wet texturing with the chemicals such as alkali (NaOH, KOH) or acid (HF, HNO 3 , CH 3 COOH) is too difficult for thinner wafer to apply due to a large amount of silicon loss. However, Plasma surface texturing using Reactive Ion Etching (RIE) can be effective in reducing the surface reflectance with low silicon loss. In this study, we have fabricated a large-area (156 Â 156 mm) multicrystalline silicon (mc-Si) solar cell by mask less surface texturing using a SF 6 /O 2 reactive ion etching. We have accomplished texturing with RIE by reducing silicon loss by almost half of that in wet texturing process. By optimizing the processing steps, we achieved conversion efficiency, open circuit voltage, short circuit current density, and fill factor as high as 16.1%, 619 mV, 33.5 mA/cm 2 , and 77.7%, respectively. This study establishes that it is possible to fabricate the thin multicrystalline silicon solar cells of low cost and high efficiency using surface texturing by RIE.
International Journal of Photoenergy, 2012
For lower reflectance, we applied a maskless plasma texturing technique using reactive ion etching (RIE) on acidic-textured multicrystalline silicon (mc-Si) wafer. RIE texturing had a deep and narrow textured surface and showed excellent low reflectance. Due to plasma-induced damage, unless the RIE-textured surfaces have the proper damage removal etching (DRE), they have a drop inVocand FF. RIE texturing with a proper DRE had sufficiently higher short circuit current(Isc)than acidic-textured samples without a drop in open circuit voltage(Voc). And in order to improve efficiency of mc-Si solar cell, we applied RIE texturing with optimized DRE condition to selective emitter structure. In comparison with the acidic-textured solar cells, RIE-textured solar cells have above 200 mA absolute gain in Isc. And optimized RIE samples with a DRE by HNO3/HF mixture showed 17.6% conversion efficiency, which were made using an industrial screen printing process with selective emitter structure.
RIE-Texturing of Industrial Multicrystalline Silicon Solar Cells
Journal of Solar Energy Engineering, 2005
Other researchers reported the development of an RIEtexturing process using Cl 2 gas, which textures many wafers per batch, making it attractive for mass-production [1]. Using this process, they have produced a 17.1% efficient 225-cm 2 mc-Si cell, which is the highest efficiency mc-Si cell of its size ever reported. This shows that RIE texturing can be done without causing performance-limiting damage to Si cells. In this paper, we will discuss an RIE-texturing process that avoids the use of toxic and corrosive Cl 2 gas.
Plasma-free Dry-chemical Texturing Process for High-efficiency Multicrystalline Silicon Solar Cells
Energy Procedia
In this paper, we study the influence of modifying the geometry of nanotexture on its electrical properties. Nanotexture is formed by an industrially feasible dry-chemical etching process performed entirely in atmospheric pressure conditions. A surface modification process is developed that allows low surface recombination velocities (S eff,min 10 cm/s) on nanotextured surfaces. By simultaneously improving the surface passivation and the emitter diffusion processes, we achieve an equivalent passivation level (V OC,impl 670 mV) for nanotextured surfaces to that of reference textured surfaces after applying either PECVD or ALD based deposition techniques.
F RIE-TEXTURED SILICON SOLAR CELLS
A maskless plasma textu~ring technique using Reac- tive Ion Etching for silicon solar cells results in a very low reflectance of 5.4 % before and 3.9 % after SiN deposi- tion. A detailed study of surface recombination and emitter properties was made, then solar cells were fabricated us- ing the DOSS solar cell process. Different plasma- damage removal treatments are tested to optimize low lifetime solar cell efficiencies. Highest efficiencies are observed for little or no plasma-damage removal etching on mc-Si. Increased & due to the RIE texture proved superior to a single layer anti-reflection coating. This indi- cates that RIE texturing is a promising texturing technique, especially applicable on lower lifetime (multicrystalline) silicon. The use of non-toxic, non-corrosive SFS makes this process attractive for mass production.
Reactive ion etching (RIE) as a method for texturing polycrystalline silicon solar cells
Solar Energy Materials and Solar Cells, 1997
Reactive ion etching (RIE) has been applied and developed as a method for texturing polycrystaUine silicon solar cells. Two structures (microgrooves and pyramids) were produced in this work. Reflectivity measurements between 400-1200 nm show an overall reflectance of 5.6% for pyramid and 7.9 % for groove structures, These results are better than those using wet anisotropic etch techniques on single-crystal silicon. RIE texturing was performed on cast polycrystalline silicon and produced better reflection control than standard TiO 2 antireflection coatings. RIE texturing also changes the incidence angle of light into the silicon, this improves the response for long wavelengths which can be utilised in thin film, polycrystalline or amorphous silicon solar cells.
Development of RIE-textured silicon solar cells
Conference Record of the Twenty-Eighth IEEE Photovoltaic Specialists Conference - 2000 (Cat. No.00CH37036), 2000
A maskless plasma texturing technique using Reactive Ion Etching for silicon solar cells results in a very low reflectance of 5.4 % before, and 3.9 % after SIN deposition. A detailed study of surface recombination and emitter properties was made, then solar cells were fabricated using the DOSS solar cell process. Different plasmadamage removal treatments are tested to optimize low lifetime solar cell efficiencies. Highest efficiencies are observed for little or no plasma-damage removal etching on mciSi. Increased Js, due to the RIE texture proved superior to a single layer anti-reflection coating. This indicates that RIE texturing is a promising texturing technique, especially applicable on lower lifetime (multicrystalline) silicon. The use of non-toxic, non-corrosive SFS makes this process attractive for mass production.
Thin Solid Films, 2013
To maximize the conversion efficiency of solar cells by improving the trapping of incident light, surface texturing of multicrystalline silicon wafers is a more permanent and effective solution to decrease reflections compared with antireflection coatings. In general, many techniques of wet chemical surface texturing depend on crystal orientation. Also, these processes place a limitation on the growth of solar production capacity due to consumption of the large amount of material, de-ionized water and chemicals. Reactive ion etching (RIE) is therefore useful for mc-Si solar cells with the random grain orientation. In this study, we have fabricated mc-Si solar cells with a large-area (156 mm × 156 mm) by a random RIE texturing method using SF 6 /O 2 plasma chemistry. A large amount of silicon loss, which is due to saw damage removal and texturing process of mc-Si wafers, have dramatically decreased by applying RIE texturing process. As a result of the optimum RIE process, the best mc-Si solar cell showed conversion efficiency, fill factor, short circuit current density, and open circuit voltages as high as 17.4%, 80%, 35 mA/cm 2 and 620 mV, respectively. This study demonstrates that it is possible to apply the thin mc-Si Solar cells fabrication for low cost and high efficiency in conventional industrial production line.
RIE surface texturing for optimum light trapping in multicrystalline silicon solar cells
Journal of the Korean Physical Society, 2012
Optical losses by reflection and transmission of the incident light should be reduced to improve the efficiency of solar cells. Compared with antireflection coatings, surface texturing is a more persistent and effective solution aiming at reducing light reflection losses. Alkali (NaOH, KOH) or acidic (HF, HNO3, CH3COOH) chemicals are used in conventional solar cell production lines for wet chemical texturing. However, Surface texturing is too difficult to apply to solar cell fabrication with thinner wafers due to the large amount of silicon loss caused by saw damage removal (SDR) and the texturing process for multicrystalline silicon (mc-Si). In order to solve the problems, reactive ion etching (RIE) has been applied for surface texturing of solar cell wafers. The RIE method can be effective in the reducing surface reflection with low silicon loss. In this study, we, therefore, fabricated a large-area (243.3 cm 2) mc-Si solar cell by maskless surface texturing using a SF6/O2 RIE process. Also, we achieved a conversion efficiency (Eff), open circuit voltage (Voc), short circuit current density (Jsc) and fill factor (FF) as high as 17.2%, 616 mV, 35.1 mA/cm 2 , and 79.6%, respectively, which are suitable for fabricating thin crystalline silicon solar cells at low cost and with high efficiency.