Tailoring Interfacial Charge Transfer for Optimizing Thermoelectric Performances of MnTe‐Sb2Te3 Superlattice‐Like Films. (17th November 2022)

• Record Type: Journal Article
• Authors: Sang, Hao; Wang, Wei; Wang, Zhengzhou; Hong, Min; Zhang, Cheng; Xie, Sen; Ge, Haoran; Yan, Fan; Wang, Zhaohui; Ouyang, Yujie; Liu, Yong; Wu, Jinsong; Liu, Wei; Tang, Xinfeng
• Is Part Of: Advanced functional materials. Volume 33:Number 3(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-11-17
• Subjects: interfacial charge transfers -- (MnTe) x(Sb 2Te 3) y -- superlattices -- thermoelectric performances -- work function difference; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202210213
• Languages: English
• ISSNs: 1616-301X

Abstract

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 (Sb2 Te3 ) 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 Sb2 Te3 layer in the SLs, originating from the work function difference between MnTe and Sb2 Te3 . By reducing the thickness of MnTe less than one monolayer, all electronic transport parameters are synergistically optimized in the quantum‐dots (MnTe) x (Sb2 Te3 )12 superlattice‐like films, leading to much improved thermoelectric power factors ( PF s). The (MnTe)0.1 (Sb2 Te3 )12 obtains the highest room‐temperature PF of 2.50 mWm −1 K −2, while the (MnTe)0.25 (Sb2 Te3 )12 possesses the highest PF of 2.79 mWm −1 K −2 at 381 K, remarkably superior to the values acquired in binary MnTe and Sb2 Te3 films. This research provides valuable guidance on understanding and rationally tailoring the interfacial charge transfer of thermoelectric SLs to further enhance thermoelectric performances. Abstract : The rational manipulation of work function difference and interfacial charge transfer is very effective in introducing the optimization effects of hole injection, energy filtering and modulation doping. This approach is validated in p‐type (MnTe) x (Sb2 Te3 ) y superlattice‐like films and quantum‐dots superlattices in order for synergistically optimized hole density p, carrier mobility μ, carrier effective mass m *, contributing to much improved thermoelectric power factor.