A novel method to extract contact resistivity for thermoelectric semiconductor

Area of Science:

• Thermoelectric materials science
• Solid-state physics
• Electrical engineering

Background:

• Contact electrical resistance significantly impacts thermoelectric module efficiency.
• Accurate measurement of contact resistivity is essential for device optimization.
• Bismuth telluride (Bi2Te3) is a key material for thermoelectric applications.

Purpose of the Study:

• To demonstrate a novel method for extracting contact resistivity in thermoelectric legs.
• To quantify the contact resistivity of n-type and p-type Bi2Te3 using a commercial instrument.
• To establish a temperature-dependent analysis of contact resistivity.

Main Methods:

• Utilized a commercial thermoelectric instrument with three probe distance options.
• Employed linear fittings between electrical resistance and probe gap for calibration and derivation.
• Calibrated probe distances using a homogeneous constantan sample.
• Investigated bismuth telluride legs connected via reflow soldering with nickel plating and Sn64Bi35Ag1 solder.

Main Results:

• Determined contact resistivity for n-type Bi2Te3 as 17.4 µΩ cm² and for p-type Bi2Te3 as 9.8 µΩ cm² at ambient temperature.
• Successfully extracted contact resistivity values at two additional temperatures.
• The proposed method allows for the determination of contact resistivity as a function of temperature.

Conclusions:

• The demonstrated method offers a reliable approach to measure contact resistivity in thermoelectric legs.
• The obtained contact resistivity values are critical for enhancing the performance of bismuth telluride thermoelectric modules.
• This technique provides valuable insights into the temperature-dependent behavior of electrical contacts in thermoelectric devices.