Enhanced light trapping based on guided mode resonance effect for thin-film silicon solar cells with two filling-factor gratings.
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.
Department of Optics and Photonics, National Central University, Jhongli, Taiwan 32054, ROC.
Yun-Chih
YC
Lee
Chian-Fu
CF
Huang
Jenq-Yang
JY
Chang
Mount-Learn
ML
Wu
D003198:Computer Simulation; D017076:Computer-Aided Design; D011211:Electric Power Supplies; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008027:Light; D008567:Membranes, Artificial; D008962:Models, Theoretical; D012031:Refractometry / Q000295:instrumentation*; D012542:Scattering, Radiation; D012993:Solar Energy; D020349:Surface Plasmon Resonance / Q000295:instrumentation*
D008567:Membranes, Artificial