Buried contact solar cell using tri-crystalline CZ silicon wafers

Tri-crystalline silicon wafers have been used for fabrication of buried contact solar cells. Optical properties and microstructures after texturing in KOH solution have been studied and compared with those of multi-crystalline silicon wafers. The textured surface of tri-crystalline wafer has a shape of V-groove with an angle of 109.48°. The efficiency of buried contact solar cell fabricated on tri-crystalline wafer measured to be 14.27% without optimization of cell process for tri-crystalline CZ wafer. Ray tracing computer simulations showed that V-groove composed of (1 1 1) after texturing can decrease reflectance significantly when cells are encapsulated. The reflectance can be reduced to about 4%, averaged over the 400–1100 nm wavelength range. The life time of tri-grain wafer was longer than that of multi-crystalline silicon wafer because it has only three twin boundaries in a wafer.