Which material properties make a semiconductor useful for thermoelectric power generation?

To determine the suitability of a semiconductor for thermoelectric power generation, engineers evaluate a specific figure of merit. This value is calculated by taking the square of the Seebeck coefficient ($\alpha$) and dividing it by the product of the material's electrical resistivity ($\rho$) and its thermal conductivity ($\kappa$).1

The three key material properties are:

• Seebeck coefficient ($\alpha$): This parameter describes the magnitude of the voltage generated in response to a temperature differential. A higher Seebeck coefficient is desirable for efficient power conversion.1
• Electrical resistivity ($\rho$): This measures the material's resistance to the flow of electric current. Lower resistivity is generally preferred to minimize power dissipation caused by ohmic heating within the device legs.1
• Thermal conductivity ($\kappa$): This represents the material's ability to conduct heat. In a thermoelectric generator, the material must balance the need to maintain a temperature differential across the legs with the necessity of managing thermal flow.1

Optimizing these properties is essential for maximizing the efficiency of thermoelectric power generators, which typically utilize p-type and n-type semiconductor legs.1