The Experts below are selected from a list of 267 Experts worldwide ranked by ideXlab platform
Wei Guo - One of the best experts on this subject based on the ideXlab platform.
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a strong oxidizing mixed acid derived high quality silicon oxide tunneling layer for polysilicon passivated Contact silicon Solar Cell
Solar Energy Materials and Solar Cells, 2018Co-Authors: Hui Tong, Yimao Wan, Mingdun Liao, Zhi Zhang, Dan Wang, Cheng Quan, Liang Cai, Pingqi Gao, Wei GuoAbstract:Abstract We developed a new wet-chemical method to grow the high-quality tunnel silicon oxide (SiOx) layer by using a strong-oxidizing mixed acid, which consists of three volumes of HNO3 (68 wt%) and one volume of H2SO4 (98 wt%), named as the CNS (concentrated nitric and sulfuric) acid for short. In comparison with the HNO3 acid, the CNS acid grows high-quality SiOx layer with the higher oxidized state at 60 °C, where the relatively low temperature avoids the significant volatilization of acid and remains the quality of acid during the extending process. The results prove that the SiOx grown in the CNS acid benefits for the surface passivation of the n-type polysilicon passivated Contact structure. An average gain of implied open circuit voltage (iVoc) by 2–10 mV and a reduction of single-side surface saturated dark current (J0) by 1–7 fA/cm2 are obtained by using the 60 °C CNS-acid grown SiOx to replace the 60 °C HNO3-acid grown one. Also, in comparison with the 90 °C HNO3 acid, the 60 °C CNS acid exhibits improved stability and repeatability for preparing the SiOx during the extending process. The CNS-acid grown SiOx helps the polysilicon passivated Contact Solar Cell to raise the efficiency by ~ 0.15% on average. In summary, the CNS acid has shown the potential for industrial application, which improves not only the manufacturing process but also the device performances.
Zhi Zhang - One of the best experts on this subject based on the ideXlab platform.
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a strong oxidizing mixed acid derived high quality silicon oxide tunneling layer for polysilicon passivated Contact silicon Solar Cell
Solar Energy Materials and Solar Cells, 2018Co-Authors: Hui Tong, Yimao Wan, Mingdun Liao, Zhi Zhang, Dan Wang, Cheng Quan, Liang Cai, Pingqi Gao, Wei GuoAbstract:Abstract We developed a new wet-chemical method to grow the high-quality tunnel silicon oxide (SiOx) layer by using a strong-oxidizing mixed acid, which consists of three volumes of HNO3 (68 wt%) and one volume of H2SO4 (98 wt%), named as the CNS (concentrated nitric and sulfuric) acid for short. In comparison with the HNO3 acid, the CNS acid grows high-quality SiOx layer with the higher oxidized state at 60 °C, where the relatively low temperature avoids the significant volatilization of acid and remains the quality of acid during the extending process. The results prove that the SiOx grown in the CNS acid benefits for the surface passivation of the n-type polysilicon passivated Contact structure. An average gain of implied open circuit voltage (iVoc) by 2–10 mV and a reduction of single-side surface saturated dark current (J0) by 1–7 fA/cm2 are obtained by using the 60 °C CNS-acid grown SiOx to replace the 60 °C HNO3-acid grown one. Also, in comparison with the 90 °C HNO3 acid, the 60 °C CNS acid exhibits improved stability and repeatability for preparing the SiOx during the extending process. The CNS-acid grown SiOx helps the polysilicon passivated Contact Solar Cell to raise the efficiency by ~ 0.15% on average. In summary, the CNS acid has shown the potential for industrial application, which improves not only the manufacturing process but also the device performances.
Mingdun Liao - One of the best experts on this subject based on the ideXlab platform.
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In-situ phosphorus-doped polysilicon prepared using rapid-thermal anneal (RTA) and its application for polysilicon passivated-Contact Solar Cells
Solar Energy Materials and Solar Cells, 2020Co-Authors: Qing Yang, Mingdun Liao, Zhixue Wang, Zheng Jingming, Yiran Lin, Xueqi Guo, Zhe Rui, Huang Dandan, Lu Linna, Mengmeng FengAbstract:Abstract A rapid thermal anneal (RTA) is used to crystallize the plasma-enhanced chemical vapor deposition (PECVD) deposited hydrogenated amorphous silicon (a-Si:H) thin film to form the phosphorus-doped polysilicon passivated Contact in tunnel oxide passivated Contact (TOPCon) Solar Cells. The effects of annealing temperature, annealing time, cooling time, and the polysilicon thickness on the surface passivation are investigated. The primary advantage of the RTA is reducing the whole crystallization period to ~15 min, shorter than the conventional tube-furnace annealing period of >60 min. We find that the RTA is a robust method to prepare high-quality polysilicon passivated Contact without introducing blistering when the thickness of the a-Si:H is less than 40 nm. The optimized RTA process leads to an implied open-circuit voltage (iVoc) of 712 mV and a single-sided dark saturation current density (J0,s) of 12.5 fA/cm2 in the as-annealed state, which is inferior to the surface passivation of the controlled one prepared by a tube furnace annealing. Fortunately, a subsequent Al2O3 capping hydrogenation improves the iVoc and J0,s to 727 mV and 4.7 fA/cm2, respectively. The champion conversion efficiency of 23.04% (Voc = 679.0 mV, Jsc = 41.97 mA/cm2 and FF = 80.86%) is achieved, which demonstrates the effectiveness of RTA for preparing a high-efficiency polysilicon passivated-Contact Solar Cell.
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a strong oxidizing mixed acid derived high quality silicon oxide tunneling layer for polysilicon passivated Contact silicon Solar Cell
Solar Energy Materials and Solar Cells, 2018Co-Authors: Hui Tong, Yimao Wan, Mingdun Liao, Zhi Zhang, Dan Wang, Cheng Quan, Liang Cai, Pingqi Gao, Wei GuoAbstract:Abstract We developed a new wet-chemical method to grow the high-quality tunnel silicon oxide (SiOx) layer by using a strong-oxidizing mixed acid, which consists of three volumes of HNO3 (68 wt%) and one volume of H2SO4 (98 wt%), named as the CNS (concentrated nitric and sulfuric) acid for short. In comparison with the HNO3 acid, the CNS acid grows high-quality SiOx layer with the higher oxidized state at 60 °C, where the relatively low temperature avoids the significant volatilization of acid and remains the quality of acid during the extending process. The results prove that the SiOx grown in the CNS acid benefits for the surface passivation of the n-type polysilicon passivated Contact structure. An average gain of implied open circuit voltage (iVoc) by 2–10 mV and a reduction of single-side surface saturated dark current (J0) by 1–7 fA/cm2 are obtained by using the 60 °C CNS-acid grown SiOx to replace the 60 °C HNO3-acid grown one. Also, in comparison with the 90 °C HNO3 acid, the 60 °C CNS acid exhibits improved stability and repeatability for preparing the SiOx during the extending process. The CNS-acid grown SiOx helps the polysilicon passivated Contact Solar Cell to raise the efficiency by ~ 0.15% on average. In summary, the CNS acid has shown the potential for industrial application, which improves not only the manufacturing process but also the device performances.
Yimao Wan - One of the best experts on this subject based on the ideXlab platform.
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a strong oxidizing mixed acid derived high quality silicon oxide tunneling layer for polysilicon passivated Contact silicon Solar Cell
Solar Energy Materials and Solar Cells, 2018Co-Authors: Hui Tong, Yimao Wan, Mingdun Liao, Zhi Zhang, Dan Wang, Cheng Quan, Liang Cai, Pingqi Gao, Wei GuoAbstract:Abstract We developed a new wet-chemical method to grow the high-quality tunnel silicon oxide (SiOx) layer by using a strong-oxidizing mixed acid, which consists of three volumes of HNO3 (68 wt%) and one volume of H2SO4 (98 wt%), named as the CNS (concentrated nitric and sulfuric) acid for short. In comparison with the HNO3 acid, the CNS acid grows high-quality SiOx layer with the higher oxidized state at 60 °C, where the relatively low temperature avoids the significant volatilization of acid and remains the quality of acid during the extending process. The results prove that the SiOx grown in the CNS acid benefits for the surface passivation of the n-type polysilicon passivated Contact structure. An average gain of implied open circuit voltage (iVoc) by 2–10 mV and a reduction of single-side surface saturated dark current (J0) by 1–7 fA/cm2 are obtained by using the 60 °C CNS-acid grown SiOx to replace the 60 °C HNO3-acid grown one. Also, in comparison with the 90 °C HNO3 acid, the 60 °C CNS acid exhibits improved stability and repeatability for preparing the SiOx during the extending process. The CNS-acid grown SiOx helps the polysilicon passivated Contact Solar Cell to raise the efficiency by ~ 0.15% on average. In summary, the CNS acid has shown the potential for industrial application, which improves not only the manufacturing process but also the device performances.
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Calcium Contacts to n‐type crystalline silicon Solar Cells
Progress in Photovoltaics: Research and Applications, 2016Co-Authors: Thomas Allen, Daniel Walter, Yimao Wan, Christian Samundsett, James Bullock, Peiting Zheng, Ben Vaughan, Matthew G. Barr, Ali Javey, Andres CuevasAbstract:Direct metallization of lightly doped n-type crystalline silicon (c-Si) is known to routinely produce non-Ohmic (rectifying) Contact behaviour. This has inhibited the development of n-type c-Si Solar Cells with partial rear Contacts, an increasingly popular Cell design for high performance p-type c-Si Solar Cells. In this contribution we demonstrate that low resistance Ohmic Contact to n-type c-Si wafers can be achieved by incorporating a thin layer of the low work function metal calcium (ϕ ~2.9 eV) between the silicon surface and an overlying aluminium capping layer. Using this approach, Contact resistivities of ρc ~ 2 mΩcm2 can be realised on undiffused n-type silicon, thus enabling partial rear Contacts Cell designs on n-type silicon without the need for a phosphorus diffusion. Integrating the Ca/Al stack into a partial rear Contact Solar Cell architecture fabricated on a lightly doped (ND = 4.5 × 1014 cm−3) n-type wafer resulted in a device efficiency of η = 17.6% where the Ca/Al Contact comprised only ~1.26% of the rear surface. We demonstrate an improvement in this Cell structure to an efficiency of η = 20.3% by simply increasing the wafer doping by an order of magnitude to ND = 5.4 × 1015 cm−3. Copyright © 2016 John Wiley & Sons, Ltd.
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Quantifying the optical losses in back-Contact Solar Cells
2014 IEEE 40th Photovoltaic Specialist Conference (PVSC), 2014Co-Authors: Keith R. Mcintosh, Teng Kho, Ngwe Zin, Evan Franklin, Da Wang, Kean Chern Fong, Simeon C. Baker-finch, Yimao Wan, Malcolm Abbott, Nicholas E. GrantAbstract:A procedure to quantify the optical loss mechanisms in back-Contact Solar Cells is presented. It incorporates recent developments in optical simulation that yield rapid and precise results. The procedure includes spectrophotometry, ellipsometry, quantum efficiency measurements, ray tracing, and the thin-film matrix method. The paper shows how experiments and simulation can be combined to quantify reflection from the front surface, absorption in the antireflection coatings, non-ideal light trapping, and free-carrier absorption—all in terms of a ‘lost generation current’. The procedure is demonstrated on a back-Contact Solar Cell with single-layer and double-layer antireflection coatings. It is extendable to other Cell structures.
Hui Tong - One of the best experts on this subject based on the ideXlab platform.
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a strong oxidizing mixed acid derived high quality silicon oxide tunneling layer for polysilicon passivated Contact silicon Solar Cell
Solar Energy Materials and Solar Cells, 2018Co-Authors: Hui Tong, Yimao Wan, Mingdun Liao, Zhi Zhang, Dan Wang, Cheng Quan, Liang Cai, Pingqi Gao, Wei GuoAbstract:Abstract We developed a new wet-chemical method to grow the high-quality tunnel silicon oxide (SiOx) layer by using a strong-oxidizing mixed acid, which consists of three volumes of HNO3 (68 wt%) and one volume of H2SO4 (98 wt%), named as the CNS (concentrated nitric and sulfuric) acid for short. In comparison with the HNO3 acid, the CNS acid grows high-quality SiOx layer with the higher oxidized state at 60 °C, where the relatively low temperature avoids the significant volatilization of acid and remains the quality of acid during the extending process. The results prove that the SiOx grown in the CNS acid benefits for the surface passivation of the n-type polysilicon passivated Contact structure. An average gain of implied open circuit voltage (iVoc) by 2–10 mV and a reduction of single-side surface saturated dark current (J0) by 1–7 fA/cm2 are obtained by using the 60 °C CNS-acid grown SiOx to replace the 60 °C HNO3-acid grown one. Also, in comparison with the 90 °C HNO3 acid, the 60 °C CNS acid exhibits improved stability and repeatability for preparing the SiOx during the extending process. The CNS-acid grown SiOx helps the polysilicon passivated Contact Solar Cell to raise the efficiency by ~ 0.15% on average. In summary, the CNS acid has shown the potential for industrial application, which improves not only the manufacturing process but also the device performances.