Large-area multicrystalline silicon solar cell fabrication using reactive ion etching (RIE)

Surface texturing of crystalline silicon wafer improves the conversion efficiency of solar cells by the enhancement in antireflection property and light trapping. Compared to antireflection coating, it is a more permanent and effective scheme. Wet texturing with the chemicals such as alkali (NaOH, KOH) or acid (HF, HNO3, CH3COOH) is too difficult for thinner wafer to apply due to a large amount of silicon loss. However, Plasma surface texturing using Reactive Ion Etching (RIE) can be effective in reducing the surface reflectance with low silicon loss. In this study, we have fabricated a large-area (156×156 mm) multicrystalline silicon (mc-Si) solar cell by mask less surface texturing using a SF6/O2 reactive ion etching. We have accomplished texturing with RIE by reducing silicon loss by almost half of that in wet texturing process. By optimizing the processing steps, we achieved conversion efficiency, open circuit voltage, short circuit current density, and fill factor as high as 16.1%, 619 mV, 33.5 mA/cm2, and 77.7%, respectively. This study establishes that it is possible to fabricate the thin multicrystalline silicon solar cells of low cost and high efficiency using surface texturing by RIE.