High thermoelectric performance realized in a BiCuSeO system by improving carrier mobility through 3D modulation...

Area of Science:

• Materials Science
• Solid State Physics
• Energy Conversion

Background:

• Thermoelectric materials convert heat to electricity.
• Bismuth copper oxyselenide (BiCuSeO) shows potential for thermoelectric applications.
• Improving carrier mobility is key to enhancing thermoelectric performance.

Purpose of the Study:

• To enhance the thermoelectric performance of BiCuSeO systems.
• To investigate the effect of modulation doping on carrier transport and thermoelectric properties.
• To achieve a high figure of merit (ZT) in BiCuSeO.

Main Methods:

• Fabrication of modulation-doped BiCuSeO heterostructures.
• Characterization of carrier transport properties, including mobility and concentration.
• Measurement of electrical conductivity, Seebeck coefficient, and thermal conductivity.
• Calculation of the thermoelectric figure of merit (ZT).

Main Results:

• Modulation doping increased carrier mobility by a factor of 2 while maintaining similar carrier concentration.
• Achieved a high power factor ranging from 5 to 10 μW cm(-1) K(-2).
• Obtained an exceptionally low thermal conductivity of ~0.25 W m(-1) K(-1) at 923 K.
• Reached a peak thermoelectric figure of merit (ZT) of approximately 1.4.

Conclusions:

• Modulation doping is an effective strategy to enhance thermoelectric performance in BiCuSeO.
• The synergistic improvement in power factor and low thermal conductivity leads to high ZT values.
• This work demonstrates the potential of BiCuSeO for efficient thermoelectric energy conversion.