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

• Published in: IEEE transactions on instrumentation and measurement Vol. 70; pp. 1 - 7
• Main Authors: Brian Pang, Chun Sum, Ng, Wessley, Liang, Jing, Qu, Qing, Martin Chau, Ho Tin, Niu, Muyao, Cheng, Man Kit, Sou, Iam Keong
• Format: Journal Article
• Language: English
• Published: New York IEEE 2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Bismuth tellurides; Conductivity; Conductivity measurement; Conductivity type measurement; Current voltage characteristics; Echoes; Electrical resistivity; Epitaxial growth; Heterostructures; Molecular beam epitaxy; P-n junctions; Physical properties; Room temperature; Seebeck coefficient; Seebeck effect; Semiconductor device measurement; semiconductor diodes; Soldering; Specialty products; Temperature measurement; thermoelectric effects; Thermoelectricity; Thin films; Voltage measurement
• ISSN: 0018-9456; 1557-9662
• DOI: 10.1109/TIM.2020.3046922

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.