Transparent silicon carbide/tunnel SiO&lt;sub&gt;2&lt;/sub&gt; passivation for c-Si solar cell front side: Enabling J&lt;sub&gt;sc&lt;/sub&gt; &amp;gt; 42 mA/cm&lt;sup&gt;2&lt;/sup&gt; and iV&lt;sub&gt;oc&lt;/sub&gt; of 742 mV

Pomaska, Manuel; Köhler, Malte; Procel Moya, P.A.; Zamchiy, Alexandr; Singh, Aryak; Kim, Do Yun; Isabella, O.; Zeman, M.; Li, Shenghao

doi:10.1002/pip.3244

Transparent silicon carbide/tunnel SiO₂ passivation for c-Si solar cell front side

Title

Transparent silicon carbide/tunnel SiO₂ passivation for c-Si solar cell front side: Enabling J_sc > 42 mA/cm² and iV_oc of 742 mV

Author

Pomaska, Manuel (Forschungszentrum Jülich GmbH)
Köhler, Malte (Forschungszentrum Jülich GmbH)
Procel Moya, P.A. (TU Delft Photovoltaic Materials and Devices)
Zamchiy, Alexandr (Russian Academy of Sciences)
Singh, Aryak (Forschungszentrum Jülich GmbH)
Kim, Do Yun (Forschungszentrum Jülich GmbH)
Isabella, O. (TU Delft Photovoltaic Materials and Devices)
Zeman, M. (TU Delft Electrical Sustainable Energy)
Li, Shenghao (Forschungszentrum Jülich GmbH; Sun Yat-sen University)

Department

Electrical Sustainable Energy

Date

2020

Abstract

N-type microcrystalline silicon carbide (μc-SiC:H(n)) is a wide bandgap material that is very promising for the use on the front side of crystalline silicon (c-Si) solar cells. It offers a high optical transparency and a suitable refractive index that reduces parasitic absorption and reflection losses, respectively. In this work, we investigate the potential of hot wire chemical vapor deposition (HWCVD)–grown μc-SiC:H(n) for c-Si solar cells with interdigitated back contacts (IBC). We demonstrate outstanding passivation quality of μc-SiC:H(n) on tunnel oxide (SiO₂)–passivated c-Si with an implied open-circuit voltage of 742 mV and a saturation current density of 3.6 fA/cm². This excellent passivation quality is achieved directly after the HWCVD deposition of μc-SiC:H(n) at 250°C heater temperature without any further treatments like recrystallization or hydrogenation. Additionally, we developed magnesium fluoride (MgF₂)/silicon nitride (SiN_x:H)/silicon carbide antireflection coatings that reduce optical losses on the front side to only 0.47 mA/cm² with MgF₂/SiN_x:H/μc-SiC:H(n) and 0.62 mA/cm² with MgF₂/μc-SiC:H(n). Finally, calculations with Sentaurus TCAD simulation using MgF₂/μc-SiC:H(n)/SiO₂/c-Si as front side layer stack in an IBC solar cell reveal a short-circuit current density of 42.2 mA/cm², an open-circuit voltage of 738 mV, a fill factor of 85.2% and a maximum power conversion efficiency of 26.6%.