Optimal Design of Silicon Solar Cells using Double Grating Structure
Abstract
In this paper, we focus on the refraction of light using gratings (in the front and back areas) in a silicon solar cell as one-dimensional crystal photonics and present the optimal structure for such cells. The front grating is provided with an anti-reflective coating on the absorbent layer (c-Si) to increase the absorption at short and medium wavelengths. We also proposed a back grating (corresponding to the front grating period) on a TCO or metal layer to increase long-wavelength absorption in a full solar cell. Based on this, the optical characteristics and short circuit current have been investigated. The Finite-Difference Time-Domain (FDTD) method is used to optimize the grating parameters for maximum adsorption in the layer (c-Si). Also, optical simulation is performed based on a silicon layer with a thickness of up to 2 micrometers using front and back grating. It can be seen that the proposed structure has about a 40.73% increase in current density compared to the case where only the anti-reflective coating used with the smaller active area is used and about 15 to 38% increase in current density compared to the cases where the front grating is used. Therefore, the proposed structure with a smaller active region thickness has a higher current density.
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