A New Vapor Texturing Method For Multicrystalline Silicon Solar Cell Applications

摘要

Multicrystalline silicon (mc-Si) solar cell fabrication is still a key issue, due to its cost effectiveness compared to crystalline silicon (c-Si). In our present work, a new technique called vapor texturing (VT) is adopted, to achieve effective texturing of mc-Si. Saw damage removal with texturing (SDRWT) using acidic solution was performed on p-type mc-Si wafers with resistivity 0.5-2 Ω cm and thickness 210 μm, using HF:HNO_3:CH_3COOH:DI water in the ratio 8:21:10:8, for 3 min. An etching depth of about 4 μm is achieved on both sides of mc-Si wafers. The SDRWT-treated mc-Si wafers were vapor textured again by HF:HNO_3 in the ratio 7:3, with 8 g of Si. The average reflectance of SDRWT-treated-only and SDRWT with vapor textured mc-Si wafers was 22.16 and 6.5%, respectively. The sheet resistance of SDRWT-treated-only and SDRWT with vapor textured mc-Si wafers was 88 and 50 Ω/□, respectively, after phosphorous doping. Subsequent to effective passivation, a sheet resistance of about 45 Ω/□ was achieved for both SDRWT-treated-only and SDRWT with vapor textured wafers. The effective minority carrier lifetime after vapor texturing and SiN_χ deposition is about 41.35 μs. Based on SEM analysis, surface morphology shows clear changes after each process.