Use of lasers in the fabrication of high-efficiency silicon solar cells

The laser grooved, buried contact approach appears to be the only practical way yet suggested of transferring recent improvements in bulk silicon laboratory cells into commercial practice. Close to 1 MW of high efficiency modules have now been produced using this improved technology. To apply the technology to polycrystalline silicon wafers, some form of surface texturing is desirable. Laser texturing has been investigated with good results. However, mechanical texturing would appear to have economic advantages. A rear junction structure also has advantages for polycrystalline substrates in cases where the diffusion length is only about the half the substrate thickness. Such structures have also been successfully implemented using the laser grooved approach. More recently, the laser grooved, buried contact approach has been adapted for use with thin film silicon layers deposited onto supporting substrates or superstrates. The strength of this approach lies in its compatibility with a parallel multijunction cell design.