Uncertainty analysis for common Seebeck and electrical resistivity measurement systems

Area of Science:

• Materials Science
• Electrical Engineering
• Metrology

Background:

• Accurate electrical property measurements are vital for thermoelectric material characterization.
• Existing measurement techniques for thermoelectric samples often lack comprehensive uncertainty analysis.
• The four-probe method is a standard for electrical resistivity and Seebeck coefficient determination.

Purpose of the Study:

• To establish and quantify measurement uncertainty for electrical resistivity and Seebeck coefficient on thermoelectric samples.
• To identify and evaluate all significant sources of uncertainty in the four-probe measurement system.
• To provide typical uncertainty ranges for practical thermoelectric device development.

Main Methods:

• Analysis of uncertainty sources in four-probe electrical measurements.
• Evaluation of cumulative error propagation for key thermoelectric parameters.
• Quantification of the cold-finger effect using thermal finite element analysis.
• Characterization of a silicon germanium thermoelectric sample.

Main Results:

• Electrical resistivity uncertainty is ±7.0% across all temperatures.
• Seebeck coefficient uncertainty is +1.0%/-13.1% at high temperatures and ±1.0% near room temperature.
• Power factor uncertainty is +7.3%/-27.0% at high temperatures and ±7.5% near room temperature.

Conclusions:

• The study provides a detailed uncertainty budget for thermoelectric electrical measurements.
• The cold-finger effect significantly impacts Seebeck coefficient accuracy, leading to over-estimation.
• The quantified uncertainties are representative of general four-probe measurement configurations for Seebeck coefficient and resistivity.