Enhanced thermoelectric properties in multilayer-modulated GeTe/Sb2Te3 films

IF 2.9 3区物理与天体物理 Q3 NANOSCIENCE & NANOTECHNOLOGY

Physica E-low-dimensional Systems & Nanostructures Pub Date : 2025-08-31 DOI:10.1016/j.physe.2025.116359

Xin Han, Guoliang Wang, Zhaoyang Liu, Yanyan Yuan, Rui Lan

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引用次数: 0

Abstract

In this work, by modulating the stacking period of the individual GeTe and Sb₂Te₃ layers, a balance between electrical conductivity and Seebeck coefficient can be achieved to maximize the thermoelectric efficiency through the synergistic effect of material design flexibility and interface engineering. The coupling of acoustic and optical branches in the phonon dispersion of Sb₂Te₃, along with the presence of multi-carrier pockets in the band structure of GeTe, offers theoretical support for constructing a multilayer structure. The multilayer films sustain the two-phase structure composed of Sb₂Te₃ and GeTe phases. As the period number increases, there is an increase in optical band gap and carrier concentration, and a decrease in resistivity. The layered interface and nanocrystalline boundary inside the multilayer films are important scattering sources and significantly reduce the carrier mobility. In addition, nano-multilayer films modulate the carrier concentration to maintain an optimal order of 10¹⁹∼10²⁰ cm⁻³. The maximum power factor of GeTe/Sb₂Te₃ multilayer films obtained is 1081 μW/mK² at 473 K for single-period film. The power factor unexpectedly decreases as the number of periods in the film increases, which could be attributed to the enhanced thickness leading to higher carrier concentration and reduced nano scale effect.

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多层调制GeTe/Sb2Te3薄膜的热电性能增强

在本研究中，通过调节GeTe和Sb2Te3单个层的叠加周期，可以通过材料设计灵活性和界面工程的协同效应，实现电导率和塞贝克系数之间的平衡，从而最大限度地提高热电效率。Sb2Te3声子色散中声光分支的耦合，以及GeTe带结构中多载流子口袋的存在，为构建多层结构提供了理论支持。多层膜保持由Sb2Te3相和GeTe相组成的两相结构。随着周期数的增加，光学带隙和载流子浓度增加，电阻率降低。多层膜内部的层状界面和纳米晶边界是重要的散射源，会显著降低载流子迁移率。此外，纳米多层膜调节载流子浓度以保持1019 ~ 1020 cm−3的最佳顺序。单周期薄膜在473 K下获得的GeTe/Sb2Te3多层膜的最大功率因数为1081 μW/mK2。随着膜周期数的增加，功率因数出人意料地降低，这可能是由于厚度的增加导致载流子浓度的增加和纳米尺度效应的降低。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Physica E-low-dimensional Systems & Nanostructures 物理-纳米科技

CiteScore

7.30

自引率

6.10%

发文量

356

审稿时长

65 days

期刊介绍： Physica E: Low-dimensional systems and nanostructures contains papers and invited review articles on the fundamental and applied aspects of physics in low-dimensional electron systems, in semiconductor heterostructures, oxide interfaces, quantum wells and superlattices, quantum wires and dots, novel quantum states of matter such as topological insulators, and Weyl semimetals. Both theoretical and experimental contributions are invited. Topics suitable for publication in this journal include spin related phenomena, optical and transport properties, many-body effects, integer and fractional quantum Hall effects, quantum spin Hall effect, single electron effects and devices, Majorana fermions, and other novel phenomena. Keywords: • topological insulators/superconductors, majorana fermions, Wyel semimetals; • quantum and neuromorphic computing/quantum information physics and devices based on low dimensional systems; • layered superconductivity, low dimensional systems with superconducting proximity effect; • 2D materials such as transition metal dichalcogenides; • oxide heterostructures including ZnO, SrTiO3 etc; • carbon nanostructures (graphene, carbon nanotubes, diamond NV center, etc.) • quantum wells and superlattices; • quantum Hall effect, quantum spin Hall effect, quantum anomalous Hall effect; • optical- and phonons-related phenomena; • magnetic-semiconductor structures; • charge/spin-, magnon-, skyrmion-, Cooper pair- and majorana fermion- transport and tunneling; • ultra-fast nonlinear optical phenomena; • novel devices and applications (such as high performance sensor, solar cell, etc); • novel growth and fabrication techniques for nanostructures