Development of a Scanning Hot Probe Technique for Thin-Film Thermoelectric Properties Characterization

This work reports on the development of a scanning hot probe technique for the measurement of thermoelectric properties of thin-films. In this method a resistively heated thermal probe of an Atomic Force Microscope (AFM) is brought in contact with the sample surface giving rise to a temperature gradient and a Seebeck voltage in the specimen. The average temperature rise of the probe is determined from the change in its electrical resistance. The heat transfer rate between the probe and the sample is estimated using a heat transfer model that takes into account the major heat transfer mechanisms in the system. The thermal conductivity is determined from the measured thermal resistance of the film. The Seebeck coefficient value is calculated using the measured temperature drop and the Seebeck voltage in the plane of the sample. The method is calibrated on glass and silicon substrates. Preliminary experimental results are presented for a thermoelectric film composed of randomly aligned Bi₂Te₃ nanowires deposited on a glass substrate.