Thermoelectrics, which can generate electricity from a temperature difference, or vice versa, is a key technology for solid-state cooling and energy harvesting; however, its applications are constrained owing to low efficiency. Since the conversion efficiency of thermoelectric devices is directly obtained via a figure of merit of materials, zT, which is related to the electronic and thermal transport characteristics, the aim here is to elucidate physical parameters that should be considered to understand transport phenomena in semiconducting materials. It is found that the weighted mobility ratio of the majority and minority carrier bands is an important parameter that determines zT. For nanograined Bi–Sb–Te alloy, the unremarked role of this parameter on temperature-dependent electronic transport properties is demonstrated. This analysis shows that the control of the weighted mobility ratio is a promising way to enhance zT of narrow bandgap thermoelectric materials.
Bibliographical noteFunding Information:
M.K. and S.‐i.K. contributed equally to this work. This research was supported by the Global Frontier Program through the Global Frontier Hybrid Interface Materials (GFHIM) project (Grant No. 2013M3A6B1078870) and the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF‐2019R1A6A1A11055660) and the Ministry of Science & ICT (NRF‐2017R1A2B3011949). This work was also supported by the Low‐dimensional Materials Genome Development by Korea Research Institute of Standards and Science (KRISS−2016‐16011070).
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All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering