TY - JOUR

T1 - Realistic efficiency potential of next-generation industrial Czochralski-grown silicon solar cells after deactivation of the boron-oxygen-related defect center

AU - Walter, Dominic C.

AU - Lim, Bianca

AU - Schmidt, Jan

N1 - This work was funded by the German State of Lower Saxony and the German Federal Ministry for Economics and Energy and by industry partners within the research project ‘SolarLife’ (contract no. 0325763C). The content is the responsibility of the authors.

PY - 2016/6/17

Y1 - 2016/6/17

N2 - We measure carrier lifetimes of different Czochralski-grown silicon (Cz-Si) materials of various boron and oxygen concentrations and determine the maximum achievable lifetime after an optimized thermal treatment. We obtain very high and stable bulk lifetimes of several milliseconds, virtually eliminating the boron–oxygen (BO) defect complex, which previously limited the carrier lifetime in boron-doped Cz-Si materials after prolonged illumination. Based on these experimental results, we introduce a new parameterization of the bulk lifetime of B-doped Cz-Si after permanent deactivation of the BO center. Notably, we measure lifetimes up to 4 ms on 2-Ωcm Cz-Si wafers at an injection level of 1/10 of the doping concentration. Importantly, these high lifetime values can be reached within 10 and 20 s of BO deactivation treatment. A detailed analysis of the injection-dependent lifetimes reveals that the lifetimes after permanent deactivation of the BO center can be well described by a single-level recombination center characterized by an electron-to-hole capture cross-section ratio of 12 and located in the middle of the silicon band gap. We implement the novel parameterization into a two-dimensional device simulation of a passivated emitter and rear solar cell using technologically realistic cell parameters. The simulation reveals that based on current state-of-the-art solar cell production technology, efficiencies reaching 22.1% are realistically achievable in the near future after complete deactivation of the BO center.

AB - We measure carrier lifetimes of different Czochralski-grown silicon (Cz-Si) materials of various boron and oxygen concentrations and determine the maximum achievable lifetime after an optimized thermal treatment. We obtain very high and stable bulk lifetimes of several milliseconds, virtually eliminating the boron–oxygen (BO) defect complex, which previously limited the carrier lifetime in boron-doped Cz-Si materials after prolonged illumination. Based on these experimental results, we introduce a new parameterization of the bulk lifetime of B-doped Cz-Si after permanent deactivation of the BO center. Notably, we measure lifetimes up to 4 ms on 2-Ωcm Cz-Si wafers at an injection level of 1/10 of the doping concentration. Importantly, these high lifetime values can be reached within 10 and 20 s of BO deactivation treatment. A detailed analysis of the injection-dependent lifetimes reveals that the lifetimes after permanent deactivation of the BO center can be well described by a single-level recombination center characterized by an electron-to-hole capture cross-section ratio of 12 and located in the middle of the silicon band gap. We implement the novel parameterization into a two-dimensional device simulation of a passivated emitter and rear solar cell using technologically realistic cell parameters. The simulation reveals that based on current state-of-the-art solar cell production technology, efficiencies reaching 22.1% are realistically achievable in the near future after complete deactivation of the BO center.

KW - Czochralski–silicon

KW - PERC

KW - boron–oxygen defect

KW - lifetime

KW - permanent recovery

KW - silicon

UR - http://www.scopus.com/inward/record.url?scp=84975275025&partnerID=8YFLogxK

U2 - 10.1002/pip.2731

DO - 10.1002/pip.2731

M3 - Article

VL - 24

SP - 920

EP - 928

JO - Progress in Photovoltaics: Research and Applications

JF - Progress in Photovoltaics: Research and Applications

SN - 1062-7995

IS - 7

ER -