Analysis of various kinds of solar cell using dynamic terahertz emission microscope

We developed a dynamic terahertz emission microscope to investigate dynamic response of photoexcited carriers in various kinds of solar cell, e.g. a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, and a GaAs solar cell. We could clearly observe the effects of carrier lifetimes of the different kinds of the solar cells. The image reflected the distribution of screening effect due to the carriers excited by pump laser pulses. Moreover, we found that the terahertz emission image was the different from electroluminescence and photoluminescence images of the polycrystalline silicon solar cell, which indicated that the terahertz emission microscopy complimented existing evaluation methods for solar cells.