Poly-Si(O)x passivating contacts for high-efficiency c-Si IBC solar cells. (September 2017)

• Record Type: Journal Article
• Authors: Yang, Guangtao; Zhang, Yue; Procel, Paul; Weeber, Arthur; Isabella, Olindo; Zeman, Miro
• Is Part Of: Energy procedia. Volume 124(2017)
• Page Start: 392
• Page End: 399
• Publication Date: 2017-09
• Subjects: poly-crystalline silicon oxide alloys -- passivating contact -- IBC c-Si solar cell; Power resources -- Congresses; Power resources -- Periodicals; Power resources; Conference proceedings; Periodicals; 333.7905
• DOI: 10.1016/j.egypro.2017.09.257
• Languages: English
• ISSNs: 1876-6102

Abstract

Abstract: Highest conversion efficiency in crystalline silicon (c-Si) solar cells can be enabled by quenching minority carriers' recombination at c-Si/contact interface owing to carrier-selective passivating contacts. With the semi-insulating poly-crystalline silicon (SIPOS, poly-Si) a very good passivation of c-Si surfaces was obtained. We have explored these passivating structures on IBC solar cells and obtained over 22% efficiency with over 23% within reach on the short term. We present in detail the passivation quality of p-type and n-type ion-implanted LPCVD poly-crystalline silicon (poly-Si) and its relation to the doping profile. Optimized poly-Si layers in the role of emitter and BSF showed excellent passivation (J0, emitter = 11.5 fA/cm 2 and J0, BSF = 4.5 fA/cm 2 ) and have been deployed in FSF-based IBC c-Si solar cells using a simple self-aligned patterning process. Applying an optimized passivation of FSF by PECVD a-Si:H/SiNx layer (J0, FSF = 6.5 fA/cm 2 ) leads to a cell with efficiency of 22.1% (VOC = 709 mV, JSC = 40.7 mA/cm 2, FF = 76.6%). Since over 83% FF has been reached with adjusted metallization technology on similar IBC structures, we believe 23% efficiency is within reach on the short term. Further improvement, especially at JSC level, is expected by deploying less absorbing carrier-selective passivating contacts based on poly-Si or wide bandgap poly-SiOx layers (J0 ~ 10 fA/cm 2 ).