Enhanced light absorption in thin-film silicon solar cells by scattering from embedded dielectric nanoparticles

• Published in: 2011 37th IEEE Photovoltaic Specialists Conference pp. 000911 - 000916
• Main Authors: Nagel, J. R., Scarpulla, M. A.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.06.2011
• Subjects: Absorption; Arrays; Dielectrics; Nanoparticles; Photovoltaic cells; Scattering; Silicon
• DOI: 10.1109/PVSC.2011.6186100
• ISBN: 9781424499663; 1424499666
• ISSN: 0160-8371

We investigate the light-trapping effects of dielectric nanoparticles embedded within the active semiconductor layer of a thin-film solar cell. The baseline model consists of a 1.0 μm slab of crystalline silicon on an aluminum back contact topped with a 75 nm Si 3 N 4 anti-reflective coating. Using finite-difference time-domain (FDTD) simulations, we calculate the absorption gain due to a periodic array of SiO 2 nanospheres with characteristic depth, diameter, and pitch. Under optimal conditions, spectrally integrated absorption gain due to embedded spheres can reach as high as 23.4 % relative to the baseline geometry. Using a geometry with an Au-core and SiO 2 shell, it is even possible to reach 30% after accounting for Ohmic losses. We also discuss the trade-offs between broadband scattering efficiency, poor absorption at long-wavelengths, and semiconductor displacement due to the embedded nanospheres.