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Si-Based Heterojunction Solar Cells Passivated by a-SiOx:H Thin Film
K. Saito, T. Takamura, Y. Ichikawa, M. Konagai
Passivation, a-Si:H, Interface(s), heterjunction, Silicon (Si) Solar Cells
Silicon Materials and Cells
Subtopic: Heterojunction Solar Cells
Event: 36th European Photovoltaic Solar Energy Conference and Exhibition
Session: 2DV.1.38
522 - 526
ISBN: 3-936338-60-4
Paper DOI: 10.4229/EUPVSEC20192019-2DV.1.38
0,00 EUR
Document(s): paper


The passivation properties of the hydrogenated amorphous silicon oxide (a-SiOx:H) film with the thin thickness applied to the Si-based heterojunction solar cells were investigate. It is confirmed that the ~2nm thickness of the a-SiOx:H film is enough to obtain the satisfactory effective lifetime of excess minority carrier using the structure passivated by the a-SiOx:H/n-type a-Si:H bilayer, although the at least 3nm overlayer of a-Si:H is necessary in the emitter side to probably protect the a-SiOx:H passivation film against the influence of p-layer deposition. The Cody gap estimated from the spectroscopic ellipsometry measurement showed that the optical bandgap of this ~2nm-thick a-SiOx:H film is narrower than that of the bulk state, which was suggested probably to be resulted from the non-steep changes of hydrogen content and from the existence of the partially epitaxial growth and/or nanocrystallized structure film at the a-SiOx:H/c-Si interface by the measurements of high resolution Rutherford backscattering spectrometry and high resolution elastic recoil detection analysis. These high passivation quality and comparably narrow bandgap of the a-SiOx:H film at the thin thickness should be beneficial to obtain high Voc and FF.