Investigation of Nanoscale Quasi Pyramid Texture for HIT Solar Cells Using n-type High Performance Multicrystalline Silicon

In this work, an n-type high performance multicrystalline silicon (nHPMC) ingot (τ >1.2 ms) was cast at NTNU. A new method to manufacture nHPMC solar cells with hetero junction solar cell architecture is presented. Texturing of the wafers is performed through silver assisted chemical etching followed by an alkaline solution treatment process. The slight differences of the reactions between the concentration of the alkali solutions and the nanopores on silicon surface has been determined and used to tailor different textures. Alkaline solutions with gradient concentration were developed to improve the surface morphology for HIT solar cells after a silver assisted chemical etching process. A homogeneous texture with quasi pyramid morphology was then obtained through balancing the reflectance and surface properties on nHPMC wafers. This kind of quasi pyramid texture is also a good starting point for the surface passivation during HIT processes. An efficiency of 19.03% has been obtained, demonstrating the potential of using n-type HPMC in the production of cost effective solar cells.