Emitter Formation and Passivation Dependence on Crystal Grain Orientations after Atmospheric Pressure Dry Nanotexturing

In this work, we investigate the emitter performance of the multicrystalline silicon (mc-Si) solar cell as a function of the crystallographic orientation of the grains and the associated texturing level. Here, we applied a plasma-less nanotexturing process by atmospheric pressure dry etching that enables low reflectivity, followed by a short anisotropic alkaline etch. It is seen in our investigation that grains with lower reflection exhibit lower emitter sheet resistance (Rsh ≈ 72 O/sq.) than that of grains with higher reflection (Rsh ≈ 79 O/sq.). We show that with our current etching process flow, there is a linear correlation between charge carrier lifetime and weighted surface reflection of different grains in a mc-Si wafer.