Apparatus for Seebeck coefficient measurement of wire, thin film, and bulk materials in the wide temperature range (80-650 K)

Abstract

A Seebeck coefficient measurement apparatus has been designed and developed, which is very effective for accurate characterization of different types of samples in a wide temperature range (80-650 K) simultaneously covering low as well as high temperature regimes. Reducing the complexity of technical design of the sample holder and data collections has always been challenging to implement in a single instrument when samples are in different geometrical shapes and electronic structures. Our unique design of the sample holder with pressure probes covers measurements of different sample shapes (wires, thin films, and pellets) as well as different resistivity ranges (metals, semiconductors, and insulators). It is suitable for characterization of different sample sizes (3-12 mm). A double heater configuration powered by using a dual channel source meter is employed for maintaining a desired constant temperature difference across the sample for the whole temperature range. Two K-type thermocouples are used for simultaneously reading temperatures and Seebeck voltages by utilizing different channels of a multichannel digital multimeter. Calibration of the system has been carried out using constantan, chromel, and alumel materials, and recorded data are found to be very accurate and consistent with earlier reports. The Seebeck coefficients of standard samples of constantan (wire) and GaN (thin film) have been reported, which shows the measurement capability of the designed setup with versatile samples.