Multi‐crystalline silicon solar cells with metal‐assisted nano‐texturing using HNO3 as hole injection agent

Abstract

In this study, metal‐assisted etching (MAE) with nitric acid (HNO3) as a hole injecting agent has been employed to texture multi‐crystalline silicon wafers. It was previously proven that addition of HNO3 enabled control of surface texturing so as to form nano‐cone shaped structures rather than nanowires. The process parameters optimized for optically efficient texturing have been applied to multi‐crystalline wafers. Fabrication of p‐type Al:BSF cells have been carried out on textured samples with thermal SiO2/PECVD‐SiNx stack passivation and screen printed metallization. Firing process has been optimized in order to obtain the best contact formation. Finally, jsc enhancement of 0.9 mA/cm2 and 0.6% absolute increase in the efficiency have been achieved. This proves that the optimized MAE texture process can be successfully used in multi‐crystalline wafer texturing with standard passivation methods. J –V curves and SEM images of the nano and iso‐textured samples. jsc enhancement of 0.9 mA/cm2 together with 0.6% absolute efficiency gain was observed on nano‐textured samples.magnified imageJ –V curves and SEM images of the nano and iso‐textured samples. jsc enhancement of 0.9 mA/cm2 together with 0.6% absolute efficiency gain was observed on nano‐textured samples.