Efficiency Potential of P-Type Al2O3/SiN Passivated PERC Solar Cells With Locally Laser-Doped Rear Contacts

• Published in: IEEE journal of photovoltaics Vol. 6; no. 3; pp. 624 - 631
• Main Authors: Ernst, Marco, Walter, Daniel, Fell, Andreas, Lim, Bianca, Weber, Klaus
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.05.2016; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Aluminum oxide; Conductivity; Contact resistance; device simulation; Geometry; Green products; laser ablation; laser doping; Lasers; passivated emitter rear contact; Photovoltaic cells; Surface morphology; Surface resistance; laser ablation; device simulation; laser doping; passivated emitter rear contact; Aluminum oxide
• ISSN: 2156-3381; 2156-3403
• DOI: 10.1109/JPHOTOV.2016.2535353

Technological restrictions on the screen-printed rear-contact feature size on the order of 100 μm are among the limiting factors of the efficiency of p-type passivated emitter rear-contact (PERC) solar cells. Simultaneous contact opening and doping using localized laser processing can overcome these design limitations. We use 3-D numerical device simulations to show that an efficiency gain of 0.3%abs compared with a screen-printed baseline cell, is possible if laser-formed point contacts of 5 μm in size with a contact recombination parameter of 5000 fA·cm -2 and a contact resistance of 10 -4 Ω·cm 2 are used. We experimentally demonstrate the implementation of simultaneous rear-surface contact opening and doping on large-area 156 × 156 mm 2 -sized PERC solar cells using ultraviolet (UV) and green laser systems. We achieve efficiencies of up to 19.9% for this process with a 10-nm atomic layer deposited Al 2 O 3 /80-nm plasma-enhanced chemical vapor deposited SiN x rear-surface dielectric stack.