Forming submicron in micron texture on the diamond-wire-sawn mc-Si wafer by introducing artificial defects

Based on a traditional acid etch system (i.e., HNO3/HF), a complex texture comprising microscale and submicroscale structures was produced on the surface of a diamond-wire-sawn (DWS) multicrystalline Si (mc-Si) wafer, upon whose surface it is typically difficult to form an effective texture for suppressing the reflection of incident light. Immersing the as-cut wafer into an HF/HNO3/AgNO3 solution introduced a large number of artificial defects onto the wafer surface. A subsequent HNO3/HF etch induced a micron texture expanded from the original DWS-induced damage as well as a submicron texture converted from the artificial defects. The multiscale textured DWS exhibited a reflectivity of similar to 19%, which is much lower than the reflectivity after only an HNO3/HF etch (similar to 28%). Therefore, the solar cell performance was improved owing primarily to improved optical antireflection and surface passivation. The method is simple and can be easily scaled up into the in-line texture process.