The effect of small pyramid texturing on the enhanced passivation and efficiency of single c-Si solar cells

In this work, a simple method to form small random pyramid texturing (0.5-2 mu m size) is proposed to enhance the surface passivation of commercial p-type Cz-Si wafers. Small pyramid texturing was generated with chemical nano-masking for anisotropic etching. The surface recombination velocity obtained after the passivation of the thermal oxide layer reduced from 65 and 10 cm s(-1) for the large pyramids (10-15 mu m size) and small pyramid (0.5-2 mu m) texturing respectively. The solar cell fabricated with large pyramid texturing resulted in an efficiency of 17.82% with a current density (J(SC)) of 36.91 mA cm(-2), an open circuit voltage (V-OC) of 620 mV whereas small pyramid texturing resulted in an efficiency of 18.5% with J(SC) of 37.6 mA cm(-2) and V-OC of 628 mV. The low surface recombination velocity increases the V-OC by 8 mV. The small pyramid textured wafers are found to enhance the quantum efficiency performance in both short and long wavelength regions.