Dual interface gratings design for absorption enhancement in thin crystalline silicon solar cells

We numerically study and analyze the light absorption enhancement in thin crystalline silicon solar cell with dual interface gratings. The structure combines the front dielectric nanowalls and the sinusoidal plasmonic grating at back reflector. We show that having specific interfaces with well-chosen period, fill factor and height can allow more efficient dielectric and plasmonic modes coupling into active layer and can improve the solar cell performance. For 1 µm active layer case, the optimal result for the proposed structure achieves short-circuit current of ~23.6 mA/cm2, which performs over 50% better than flat solar cell structure, the short-circuit current of which is ~15.5 mA/cm2. In addition, the active layer thickness and angular analysis show that the proposed structure maintains its advantage over flat structure.