Open AccessEnhanced light trapping based on guided mode resonance effect for thin-film silicon solar cells with two filling-factor gratings
Author(s) -
Yun-Chih Lee,
ChienFeng Huang,
Jenq Yang Chang,
Mount-Learn Wu
Publication year - 2008
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.16.007969
Subject(s) - materials science , optics , guided mode resonance , grating , optoelectronics , thin film , absorption (acoustics) , silicon , trapping , resonance (particle physics) , solar cell , plasmonic solar cell , ray , diffraction grating , polymer solar cell , physics , ecology , particle physics , nanotechnology , biology
An approach of enhanced light-trapping in a thin-film silicon solar cell by adding a two-filling-factor asymmetric binary grating on it is proposed for the wavelength of near-infrared. Such a grating-on-thin-film structure forms a guided-mode resonance notch filter to couple energy diffracted from an incident wave to a leakage mode of the guided layer in the solar cell. The resonance wave coupled between two-filling-factor gratings would laterally extend the optical power and induce multiple bounces within the active layer. The resonance effect traps light in the cell enhancing its absorption probability. A dynamic light-trapping behaviour in solar cells is observed. A photon dwelling time is proposed for the first time to quantify the light-trapping effect. Moreover, the light absorption probability is also quantified. As compared the grating-on-thin-film structure with the one of planar silicon thin film, simulation results reveal that it is 3-fold enhancement in the light absorption within a spectral range of 920-1040 nm. Moreover, such an enhancement can be maintained even the incident angle of near-IR broadband light wave varies up to +/-40 degrees.