Back contact monocrystalline thin-film silicon solar cells from the porous silicon process

We develop a back contact monocrystalline thin-film silicon solar cell using the porous silicon process. Laser processes are applied for all structuring steps. Thus no photolithography or other masking techniques are required. A single evaporation step is used to metallize the cell. Laser scribing is used for contact separation. The cell has a planar front surface, an area of 79.2 cm 2 and a cell thickness of 30 ¿m. We reach an efficiency of 13.5 %. The open-circuit voltage is 633 mV and the short-circuit current density is 28.7 mA/cm 2 .