For use in solar cell inspection, Sensors Unlimited Inc., part of Goodrich Corp., has released InGaAs-based shortwave infrared (SWIR) area- and line-scan cameras that operate between 0.9 and 1.7 μm. They reveal voids in silicon boules, bricks and ingots before those materials are sliced into wafers to produce mono- and multicrystalline solar cells. The cameras detect hidden cracks by mapping stress in raw wafers, finished cells and thin films made for solar electricity-generating panels. They spot saw marks on the opposite side of a silicon wafer as well as defects inside the material. By applying forward bias to cells to generate electroluminescence, the cameras can gauge cell efficiency and uniformity.