The van der Pauw method is a technique used to measure the electrical properties of thin, flat samples, such as semiconductors and metals. It involves placing four electrical contacts on the periphery of a sample and applying current through two contacts while measuring the voltage across the other two. This allows for the determination of resistivity and Hall effect properties. This method is particularly useful for materials that do not have a uniform shape, as it provides accurate results regardless of the sample's geometry. The van der Pauw technique is widely used in research and industry to characterize new materials and improve electronic devices.