Effects of vacuum annealing on the electron mobility of epitaxial La-doped BaSnO3 films
Effects of vacuum annealing on the electron mobility of epitaxial La-doped BaSnO3 films
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DOI：
10.1063/1.5054154
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发表时间：
2019-02-01
期刊：
影响因子：
6.1
通讯作者：
Ohta, Hiromichi
中科院分区：
文献类型：
--
作者：
Cho, Hai Jun;Onozato, Takaki;Ohta, Hiromichi
宽带隙（E-g接近3.1 eV）La掺杂BaSnO3（LBSO）作为透明氧化物半导体之一越来越受到人们的关注，因为其体单晶表现出高载流子迁移率（接近320 cm(2) V-1 s(-1)）和高载流子浓度（接近10(20) cm(-3)）。因此，迄今为止，许多研究人员已经制备了LBSO外延薄膜，但由于晶格/结构缺陷的形成，与单晶相比，可获得的载流子迁移率明显较低。在这里，我们报告说，LBSO 薄膜中的迁移率抑制可以通过简单的真空退火工艺来解除。真空退火产生的氧空位降低了 MgO 基底上 LBSO 薄膜的热稳定性，从而增加了高温下的载流子浓度和横向晶粒尺寸。结果，载流子迁移率大大提高，这是在空气中热处理后不会发生的。我们报告了 MgO 基底上 LBSO 薄膜真空退火的因子设计实验，并讨论了结果的含义。我们的研究结果扩展了我们目前关于外延 LBSO 薄膜点缺陷形成的知识，并表明真空退火是提高 LBSO 薄膜迁移率值的有力工具。 (C) 2018 年作者。
Wide bandgap (E-g similar to 3.1 eV) La-doped BaSnO3 (LBSO) has attracted increasing attention as one of the transparent oxide semiconductors since its bulk single crystal shows a high carrier mobility (similar to 320 cm(2) V-1 s(-1)) with a high carrier concentration (similar to 10(20) cm(-3)). For this reason, many researchers have fabricated LBSO epitaxial films thus far, but the obtainable carrier mobility is substantially low compared to that of single crystals due to the formation of the lattice/structural defects. Here we report that the mobility suppression in LBSO films can be lifted by a simple vacuum annealing process. The oxygen vacancies generated from vacuum annealing reduced the thermal stability of LBSO films on MgO substrates, which increased their carrier concentrations and lateral grain sizes at elevated temperatures. As a result, the carrier mobilities were greatly improved, which does not occur after heat treatment in air. We report a factorial design experiment for the vacuum annealing of LBSO films on MgO substrates and discuss the implications of the results. Our findings expand our current knowledge on the point defect formation in epitaxial LBSO films and show that vacuum annealing is a powerful tool for enhancing the mobility values of LBSO films. (C) 2018 Author(s).