SiO_yN_x/SiN_x stack: a promising surface passivation layer for high-efficiency and potential-induced degradation resistant mc-silicon solar cells

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• 作者：Chunlan Zhou ; Junjie Zhu ; Su Zhou ; Yehua Tang ; Sean E. Foss ; Halvard Haug ; Ø ; rnulf Nordseth ; Erik S. Marstein and Wenjing Wang
• 刊名：Progress in Photovoltaics: Research and Applications
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：25
• 期：1
• 页码：23-32
• 全文大小：951K
• ISSN：1099-159X

文摘

A thin SiO_yN_x film was inserted below a conventional SiN_x antireflection coating used in c-Si solar cells in order to improve the surface passivation and the solar cell's resistance to potential-induced degradation (PID). The effect of varying the flow ratio of the N₂O and SiH₄ precursors and the deposition temperature for the SiO_yN_x thin film upon material properties were systematically investigated. An excellent surface passivation was obtained on FZ p-type polished silicon wafers, with the best results obtained with a SiO_yN_x film deposited at a very low temperature of 130 °C and with an optical refractive index of 1.8. In the SiO_yN_x/SiN_x stack structure, a SiO_yN_x film with ~6 nm thickness is sufficient to provide excellent surface passivation with an effective surface recombination velocity S_eff < 2 cm/s. Furthermore, we applied the optimized SiO_yN_x/SiN_x stack on multicrystalline Si solar cells as a surface passivation and antireflection coating, resulting in a 0.5% absolute average conversion efficiency gain compared with that of reference cells with conventional SiN_x coating. Moreover, the cells with the SiO_yN_x/SiN_x stack layers show a significant increase in their resistance to PID. Nearly zero degradation in shunt resistance was obtained after 24 h in a PID test, while a single SiN_x-coated silicon solar cell showed almost 50% degradation after 24 h. Copyright