Influence of wavelength on laser doping and laser-fired contact processes for c-Si solar cells

Carlos Molpeceres; María Isabel Sánchez-Aniorte; Miguel Morales; David Muñoz; Isidro Martín; Pablo Ortega; Mónica Colina; Cristóbal Voz; Ramón Alcubilla

doi:10.1117/12.929456

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12 October 2012 Influence of wavelength on laser doping and laser-fired contact processes for c-Si solar cells

Carlos Molpeceres, María Isabel Sánchez-Aniorte, Miguel Morales, David Muñoz, Isidro Martín, Pablo Ortega, Mónica Colina, Cristóbal Voz, Ramón Alcubilla

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Proceedings Volume 8473, Laser Material Processing for Solar Energy; 847308 (2012) https://doi.org/10.1117/12.929456
Event: SPIE Solar Energy + Technology, 2012, San Diego, California, United States

Abstract

This work investigates the influence of the laser wavelength on laser doping (LD) and laser-fired contact (LFC) formation in solar cell structures. We compare the results obtained using the three first harmonics (corresponding to wavelengths of 1064 nm, 532 nm and 355 nm) of fully commercial solid state laser sources with pulse width in the ns range. The discussion is based on the impact on the morphology and electrical characteristics of test structures. In the case of LFC the study includes the influence of different passivation layers and the assessment of the process quality through electrical resistance measurements of an aluminium single LFC point for the different wavelengths. Values for the normalized LFC resistance far below 1.0 mΩcm² have been obtained, with better results at shorter wavelengths. To assess the influence of the laser wavelength on LD we have created n+ regions into p-type c-Si wafers, using a dry LD approach to define punctual emitters. J-V characteristics show exponential trends at mid-injection for a broad parametric window in all wavelengths, with local ideality factors well below 1.5. In both processes the best results have been obtained using green (532 nm) and, specially, UV (355 nm). This indicates that to minimize the thermal damage in the material is a clear requisite to obtain the best electrical performance, thus indicating that UV laser shows better potential to be used in high efficiency solar cells.

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Carlos Molpeceres, María Isabel Sánchez-Aniorte, Miguel Morales, David Muñoz, Isidro Martín, Pablo Ortega, Mónica Colina, Cristóbal Voz, and Ramón Alcubilla "Influence of wavelength on laser doping and laser-fired contact processes for c-Si solar cells", Proc. SPIE 8473, Laser Material Processing for Solar Energy, 847308 (12 October 2012); https://doi.org/10.1117/12.929456

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