Insights into nucleation engineering in Si pyramidal texturing for high performance heterojunction solar cells applications

摘要

Enhancing light trapping, converting photons with least losses into electric charges, and efficiently extracting photo-generated charges to the external load are the challenge for all photovoltaic technologies. For crystalline silicon (c-Si) photovoltaic devices, all these factors depend heavily on the morphological characteristics of the silicon substrates. Here we have elucidated the role of saw-damage etching (SDE) in promoting the morphological characteristics of the micro-pyramidal textured silicon wafer, in particular exploring its effects on enhancing light trapping ability and improving the hydrogenated amorphous silicon (a-Si:H)/c-Si hetero-interface properties. By analyzing the etching kinetics model of the texturing process, we propose that the SDE process could act a role of placing nucleation sites for the subsequent texturing process. An appropriate SDE process could achieve large and discrete pyramids (similar to 8 mu m) coverage for the silicon surface. By applying the optimized SDE process on fabricating of silicon heterojunction solar cells, an efficiency of 19.9% could be achieved. This results indicate that adjusting the nucleation sites for the texturing process could effectively control the morphological properties of the final formed substrates, which also trigger new approaches of tuning silicon morphology and structuring for various applications. (C) 2018 Elsevier B.V. All rights reserved.