A new vapor texturing method for multicrystalline silicon solar cell applications

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:HNO3:CH3COOH: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:HNO3 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 SiNx deposition is about 41.35 μs. Based on SEM analysis, surface morphology shows clear changes after each process.