A Simple Thermoelectric Effect Setup for Determining the Conductivity Type of Thin Film Materials

In this article, we present a simple and low-cost experimental setup for thermoelectric effect measurements of thin film materials near room temperature, which can be used to determine their conductivity types. Bi 2 Te 3 and Sb 2 Te 3 thin films grown by the molecular beam epitaxy technique were used as the tested samples. Their Seebeck coefficients were determined to be (-141 ± 1) μV/K and (39 ± 2) μV/K, respectively, confirming that the former is an n-type material and the latter is a p-type material. A heterostructure composed of Sb2Te3 and Bi2Te3 was characterized by electrical transport measurements. Data fitting was carried out for its current-voltage characteristics with the Shockley diode model and a real diode model proposed by Cataldo et al., and some physical parameters of the heterostructure were extracted, including its ideality factor and saturation current. Based on its rectifying current-voltage behavior, we confirm that the aforementioned heterostructure is a p-n junction, which echoes the contrast in the conductivity types of Sb 2 Te 3 and Bi 2 Te 3 as determined by the thermoelectric effect measurements.