P-Type Indium-Doped Passivated Emitter Rear Solar Cells (PERC) on Czochralski Silicon Without Light-Induced Degradation

• Published in: IEEE journal of photovoltaics Vol. 6; no. 4; pp. 795 - 800
• Main Authors: Eunhwan Cho, Young-Woo Ok, Upadhyaya, Ajay D., Binns, Martin Jeff, Appel, Jesse, Guo, Jason, Rohatgi, Ajeet
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.07.2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Aluminum; Boron; Conductivity; Czochralski process; Czochralski silicon; Degradation; Emitters; full aluminum back-surface field (Al-BSF) structure; Gallium; Indium; light-induced degradation; Oxides; p-type; passivated emitter rear cells; Photovoltaic cells; Silicon; Solar cells; light-induced degradation; full aluminum back-surface field (Al-BSF) structure; indium; p-type; solar cells; Czochralski silicon; passivated emitter rear cells
• ISSN: 2156-3381; 2156-3403
• DOI: 10.1109/JPHOTOV.2016.2547578

Solar cells fabricated on boron (B)-doped Czochralski (Cz) Si wafers in the photovoltaic industry are known to suffer from light-induced degradation (LID) in efficiency. This paper reports on promising LID-free large-area indium (In)-doped Cz Si solar cells. Two different commercial-grade B-doped Cz materials were included for comparison. To study the impact of LID on the cell structure, ion-implanted large-area (239 and 242.22 cm 2 ) screen-printed full aluminum (Al) back-surface field (BSF) baseline cells, as well as higher performance passivated emitter rear cells (PERC) with oxide passivation and local Al BSF, were fabricated. In-doped PERC cells achieved 20.3% efficiency, while the B-doped cells gave efficiencies of 20.7% and 20.5% from low- (2 Ω·cm) and high-resistivity (6.2 Ω·cm) substrates, respectively. It was found that initial efficiency of In-doped PERC cells was ~0.2% lower due to lower bulk lifetime and higher back-surface recombination velocity. However, In-doped PERC cells showed no LID and surpassed the B-doped PERC cell efficiency by 0.3-0.5% after 0.8-sun 48-h illumination at 37 °C.