Electrical conductivity determination of semiconductors by utilizing photography, finite element simulation and resistance measurement

A new method is developed to measure precisely and reliably the electrical conductivity of a block-shaped semiconductor specimen using four-wire technique with electrodes in arbitrary shape and position. No effort for accurate electrode preparation is necessary anymore. This method may be especially applied to measure the conductivity of ceramics at high temperatures, when typical spring-contacts or clamp-contacts are not possible and instead wound wires are used for electrically contacting the specimen. The method comprises the following: An image of the specimen is processed to a 3D model. By applying a finite element simulation on this 3D model, a form factor (also called geometry factor) that considers the effect of the non-infinitesimally small electrodes is calculated. Together with the measured resistance (preferably in four-wire technique), the actual conductivity of the sample is derived. Experimental results confirmed the validity of the proposed method. As a limitation of the method, the conductivity of the specimen should be within the range of 0.01 Sm-1 and 10(6) Sm-1.