层状Bi_(1–x)Sb_(x)Se纳米薄膜的制备及其热电性能研究  

Preparation and thermoelectric properties of layered Bi_(1–x)Sb_(x)Se nanocrystalline films

作　　者：许静 何梓民 杨文龙 吴荣[2] 赖晓芳 简基康[1] Xu Jing;He Zi-Min;Yang Wen-Long;Wu Rong;Lai Xiao-Fang;Jian Ji-Kang(School of Physics and Optoelectronic Engineering,Guangdong University of Technology,Guangzhou 510006,China;School of Physical Science and Technology,Xinjiang University,Xinjiang 830046,China)

机构地区：[1]广东工业大学,物理与光电工程学院,广州510006 [2]新疆大学,物理科学与技术学院,新疆830046

出　　处：《物理学报》2022年第19期282-290,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:52072078,51702058)资助的课题。

摘　　要：Bi_(2)Se_(3)是近年来发现的具有超低本征晶格热导率材料,显示出比传统的Bi_(2)Se_(3)更高的热电性能潜力.本文采用真空热蒸发法制备了具有(001)取向生长的N型纯相Bi_(2)Se_(3)纳米晶薄膜,并通过Sb共蒸发,制备得到不同掺杂浓度的Bi_(1-x)Sb_(x)Se热电薄膜.对薄膜样品物相、形貌、组份、晶格振动、化学价态及电输运性质进行了表征.结果显示,Sb进入到Bi_(2)Se_(3)晶格中取代了Bi原子的位置,而Sb原子与Bi原子之间的金属性差异使得掺杂后的样品载流子浓度下降,塞贝克系数上升.同时,随着Sb掺杂浓度的增大,组成薄膜的纳米晶粒尺寸减小,薄膜面内形成更加致密的层状结构,有利于载流子输运,导致样品的载流子迁移率由13.6 cm^(2)/(V·s)显著提升至19.3 cm^(2)/(V·s).受到Seebeck系数与电导率的综合作用,Bi_(0.76)Sb_(0.24)Se薄膜具有2.18μW/(cm·K~2)的室温功率因子,相对于未掺杂Bi_(2)Se_(3)薄膜功率因子得到提升.本工作表明Bi_(2)Se_(3)基薄膜在近室温热电薄膜器件中具有潜在的应用前景.Bi_(2)Se_(3)is found to be a promising near-room-temperature thermoelectric material with higher performance than traditional Bi_(2)Se_(3)due to its ultra-low intrinsic lattice thermal conductivity.In this work,N-type Bi_(2)Se_(3)nanocrystalline thin films with(001)preferred orientation are first prepared via vacuum thermal evaporation method,and Bi_(1-x)Sb_(x)Se nanocrystalline films with different doping concentrations are obtained by Sb coevaporation.The phases,morphologies,chemical compositions and valences,lattical vibrations,and electrical properties of these films are characterized.It is found that the Sb dopant successfully enters into the crystal lattice and replaces the Bi site of Bi_(2)Se_(3)quintuple layers and Bibilayers without selectivity,and the difference of gold properties between Sb atom and Bi atoms leads the carrier concentration to sharply decrease and the Seebeck coefficient in doped Bi_(2)Se_(3)to increase.Meanwhile,the sizes of nanocrystals in the films decrease and the denser layered structure is formed due to the Sb doping,which is conducive to the carrier transport in the samples,and the in-plane carrier mobility of the films effectively increases from 13.6 cm^(2)·V·s(Bi_(2)Se_(3))to 19.3 cm^(2)·V·s(Bi_(0.76)Sb_(0.24)Se).The maximum roomtemperature power factor of 2.18μW·cm·Kis obtained in Bi_(0.76)Sb_(0.24)Se,which is higher than that in undoped Bi_(2)Se_(3).The results of this work indicate that the Bi_(2)Se_(3)-based thin films have potential applications in room temperature thermoelectric thin film devices.

关 键 词：N型 Bi_(1–x)Sb_(x)Se 热电纳米晶薄膜 层状结构 功率因子 

分 类 号：TB383.2[一般工业技术—材料科学与工程]