We report the thermoelectric properties of undoped hot-pressed In4Se3−x (x = 0.05). Stoichiometric imbalance due to selenium deficiency in In4Se3 was found to create a secondary phase of elemental indium in the host material. Heat treatment drove grain growth and increased the indium solubility in In4Se3. Indium-rich domains at grain surfaces/boundaries in untreated samples were found to redistribute inside the grains and their junctions after heat treatment. Due to enhanced phonon scattering by secondary phase of indium, very low values of thermal conductivity were observed for all samples, leading to a maximum thermoelectric figure of merit (zT) of 1.13 at 723 K along the hot-pressing direction for the heat-treated sample.
Bibliographical noteFunding Information:
This work was supported by Mid-career Researcher Program (No. 2011-0028729) and Nano-Material Technology Development Program (Green Nano Technology Development Program) (No. 2011-0030146) through the National Research Foundation of Korea (NRF) grant funded by the Ministry of Education, Science, and Technology (MEST) and by an Energy Efficiency & Resources Program (No. 20112010100100)?of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korean Government Ministry of Knowledge Economy.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering
- Materials Chemistry