Thermoelectric Property in Orthorhombic-Domained SnSe Film

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Single-crystal tin selenide (SnSe) demonstrates exceptional thermoelectric properties, making SnSe films a target for practical applications.
• However, achieving comparable high thermoelectric performance in SnSe films and understanding their nanostructure-property relationships remain challenges.

Purpose of the Study:

• To prepare alpha-axis-oriented epitaxial SnSe films.
• To investigate the thermoelectric properties and nanostructure of these SnSe films.
• To elucidate the influence of nanostructure on thermoelectric performance.

Main Methods:

• Fabrication of alpha-axis-oriented epitaxial SnSe films.
• Characterization of film nanostructure, including domain boundaries.
• Measurement of electrical conductivity and thermoelectric properties (power factor) across a temperature range.

Main Results:

• SnSe films exhibited significantly lower electrical conductivity than single crystals at room temperature.
• Surprisingly, the power factor of SnSe films surpassed that of single crystals at high temperatures (around 300 °C).
• Orthorhombic domain boundaries, observed with spacing of several hundred nanometers, caused carrier scattering, reducing mobility at room temperature but with diminished effect at higher temperatures.

Conclusions:

• Carrier scattering at domain boundaries leads to a unique temperature dependence of thermoelectric properties in SnSe films.
• High thermoelectric performance was achieved in SnSe films even with the presence of domain boundaries.
• This demonstrates the potential for developing high-performance SnSe thermoelectric films for practical applications.