Experimental Identification of Critical Condition for Drastically Enhancing Thermoelectric Power Factor of Two-Dimensional Layered Materials

• DOI: 10.1021/acs.nanolett.8b03026
• Publication Date: 2018-11-27T18:11:09Z
• Authors: Junwen Zeng; Xin He; Shi-Jun Liang; Erfu Liu; Yuanhui Sun; Chen Pan; Yu Wang; Tianjun Cao; Xiaowei Liu; Chenyu Wang; Lili Zhang; Shengnan Yan; Guangxu Su; Zhenlin Wang; Kenji Watanabe; Takashi Taniguchi; David J. Singh; Lijun Zhang; Feng Miao
• Keywords: Ballistic conduction

Nanostructuring is an extremely promising path to high-performance thermoelectrics. Favorable improvements in thermal conductivity are attainable many material systems, and theoretical work points large electronic properties. However, realization of the benefits practical materials has been elusive experimentally. A key challenge that experimental identification quantum confinement length, below which thermoelectric power factor significantly enhanced, remains due lack simultaneous control size carrier density. Here we investigate gate-tunable temperature-dependent transport γ-phase indium selenide (γ-InSe, n-type semiconductor) samples with thickness varying from 7 29 nm. This allows us properly map out dimension doping space. Combining studies, reveal sharper pre-edge conduction-band density states arising gives rise enhancement Seebeck coefficient thinner InSe samples. Most importantly, experimentally identify role competition between length de Broglie wavelength factor. Our results provide important general guideline for optimizing improving performance two-dimensional layered semiconductors.