Tailoring Interfacial Charge Transfer for Optimizing Thermoelectric Performances of MnTe-Sb2Te3 Superlattice-Like Films |
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| Authors: | Hao Sang Wei Wang Zhengzhou Wang Min Hong Cheng Zhang Sen Xie Haoran Ge Fan Yan Zhaohui Wang Yujie Ouyang Yong Liu Jinsong Wu Wei Liu Xinfeng Tang |
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| Affiliation: | 1. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, 430070 China;2. Centre for Future Materials, University of Southern Queensland, Springfield Central, Brisbane, Queensland, 4300 Australia;3. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, 430070 China International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, 430070 China;4. School of Physics and Technology and The Key Laboratory of Artificial Micro/Nano Structures of Ministry of Education, Wuhan University, Wuhan, 430072 China |
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| Abstract: | Interfacial charge transfer has a vital role in tailoring the thermoelectric performance of superlattices (SLs), which, however, is rarely clarified by experiments. Herein, based on epitaxially grown p-type (MnTe)x(Sb2Te3)y superlattice-like films, synergistically optimized thermoelectric parameters of carrier density, carrier mobility, and Seebeck coefficient are achieved by introducing interfacial charge transfer, in which effects of hole injection, modulation doping, and energy filtering are involved. Carrier transport measurements and angle-resolved photoemission spectroscopy (ARPES) characterizations reveal a strong hole injection from the MnTe layer to the Sb2Te3 layer in the SLs, originating from the work function difference between MnTe and Sb2Te3. By reducing the thickness of MnTe less than one monolayer, all electronic transport parameters are synergistically optimized in the quantum-dots (MnTe)x(Sb2Te3)12 superlattice-like films, leading to much improved thermoelectric power factors (PFs). The (MnTe)0.1(Sb2Te3)12 obtains the highest room-temperature PF of 2.50 mWm−1K−2, while the (MnTe)0.25(Sb2Te3)12 possesses the highest PF of 2.79 mWm−1K−2 at 381 K, remarkably superior to the values acquired in binary MnTe and Sb2Te3 films. This research provides valuable guidance on understanding and rationally tailoring the interfacial charge transfer of thermoelectric SLs to further enhance thermoelectric performances. |
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| Keywords: | interfacial charge transfers (MnTe)x(Sb2Te3)y superlattices thermoelectric performances work function difference |
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