Fig. 2: Structural characterization of the c-Si/SiOX/poly-Si interface of TOPCon solar cells.
a, b HRTEM images of the c-Si/SiOX/poly-Si interface of the high-PCE and low-PCE cells, showing local variations in the oxide thickness at the interface. The yellow dashed line indicates the initial oxide interface. c–h HAADF-STEM images and EELS measurements of the c-Si/ SiOX/poly-Si interface for high-PCE and low-PCE cells. c, d The blue rectangular dashed areas of (a, b), respectively, and are shown at higher magnification. The yellow dashed line indicates the magnified oxide interface, and the red rectangular dashed area indicates the location of the pinhole. e–h The O-K side and Si-K side EELS maps of the oxide interface in (c, d), respectively. The elemental content variations are basically corresponding to the pinhole positions in (c, d). The EELS line profiles obtained at similar locations in (g, h) clearly show the presence of oxygen at the passivating pinhole locations. a–d Scale bars, 5 nm.
