p-n Transition in Thermoelectric Semiconductor Eskebornite

Area of Science:

• Materials Science
• Solid-State Physics
• Inorganic Chemistry

Background:

• Eskebornite (CuFeSe2) is a I-III-VI2 semiconductor with limited experimental investigation.
• Its electrical and magnetic properties suggest potential for thermoelectric applications.
• Understanding doping effects is crucial for optimizing thermoelectric materials.

Purpose of the Study:

• To synthesize and characterize Ni-doped eskebornite (Cu1-xNixFeSe2) via solid-state methods.
• To investigate the impact of Ni doping on the thermoelectric properties of eskebornite.
• To explore the temperature-dependent p-n transition and optimize thermoelectric performance.

Main Methods:

• Solid-state synthesis involving mechanical alloying and hot pressing.
• X-ray diffraction for phase analysis.
• Thermoelectric property measurements (Seebeck coefficient, electrical conductivity, thermal conductivity) from 323 K to 623 K.

Main Results:

• Successful synthesis of Ni-doped eskebornite with a minor secondary penroseite phase.
• Observed temperature-dependent p-n transition in the Seebeck coefficient, shifting to lower temperatures with increased Ni doping.
• Electrical conductivity decreased with Ni doping, while thermal conductivity increased.
• Maximum thermoelectric figure of merit (ZT) values of 0.30 × 10^-3 (p-type) and 0.55 × 10^-3 (n-type) were achieved.

Conclusions:

• Ni doping effectively modifies the thermoelectric properties of eskebornite.
• The observed p-n transition offers tunable thermoelectric behavior.
• The study demonstrates potential for Ni-doped eskebornite in thermoelectric devices.