Current vector distribution in semiconductor observed by laser SQUID microscope with needle

A laser SQUID microscope can obtain the current vector distribution in semiconductor using magnetic field obtained by a laser beam offset method. Using an electromagnetic simulation, a proximate sinusoidal relation between current vector and the corresponding magnetic field was obtained. The experiment was carried out with a polycrystalline silicon solar cell as a sample. Two images of magnetic field were obtained when a laser point on the sample surface was 1 mm displaced in x- or y-direction, respectively. Current vector distribution in the solar cell was clearly observed by this method. This technique is useful to evaluate photoelectronic materials