A setup to measure the Seebeck coefficient and electrical conductivity of anisotropic thin-films on a single sample

This work documents an all-in-one custom setup that allows us to measure the in-plane Seebeck coefficients and electrical conductivities of anisotropic thin film samples close to room temperature. Both pairs, S_∥ and σ_∥ and S_⊥ and σ_⊥, can be measured using four contacts on the same sample, reducing measurement time and minimizing potential sources of error due to aggregating data from several distinct samples. The setup allows us to measure the electrical conductivity of isotropic samples using the well-known van der Pauw method. For samples with in-plane anisotropy, the two components σ_∥ and σ_⊥ can be extracted from the same type of measurements by performing additional calculations. Using the same contacts, the Seebeck coefficient along one direction is measured using a differential steady-state method. After rotating the sample by 90°, the orthogonal Seebeck component can be measured. In order to show the generality of the method, we measure different types of samples, from metal references to oriented doped conjugated polymers.