Structural, optical, and electrical properties of strained La-doped SrTiO3 films
Structural, optical, and electrical properties of strained La-doped SrTiO3 films
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DOI：
10.1063/1.4891225
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发表时间：
2014-07-28
影响因子：
3.2
通讯作者：
Demkov, Alexander A.
中科院分区：
文献类型：
--
作者：
Choi, Miri;Posadas, Agham B.;Demkov, Alexander A.
研究了应变la掺杂SrTiO3外延薄膜的结构、光学和室温电学性能。通过分子束外延在LaAlO3、（LaAlO3）（0.3）（Sr2AlTaO6）（0.7）、SrTiO3和DyScO3四种不同的衬底上生长出了浓度为5 ~ 25%的导电镧掺杂SrTiO3薄膜，其晶格错配应变范围为-2.9% ~ +1.1%。我们比较了La浓度和应变对结构和光学性能的影响，并测量了它们对室温下电阻率和迁移率的影响。根据应变和La浓度的不同，室温电阻率范围为10（-2）至10(-5)ω cm。无论应变的符号如何，室温迁移率随应变的增加而降低。从椭圆偏振光谱中观察到的Drude峰和Burstein-Moss位移清楚地证实了La的加入在SrTiO3中产生了高密度的自由载流子。通过第一性原理计算来了解la掺杂对态密度、有效质量、电导率和直流弛豫时间的影响。(C) 2014 AIP出版有限责任公司
The structural, optical, and room-temperature electrical properties of strained La-doped SrTiO3 epitaxial thin films are investigated. Conductive La-doped SrTiO3 thin films with concentration varying from 5 to 25% are grown by molecular beam epitaxy on four different substrates: LaAlO3, (LaAlO3)(0.3)(Sr2AlTaO6)(0.7), SrTiO3, and DyScO3, which result in lattice mismatch strain ranging from -2.9% to +1.1%. We compare the effect of La concentration and strain on the structural and optical properties, and measure their effect on the electrical resistivity and mobility at room temperature. Room temperature resistivities ranging from similar to 10(-2) to 10(-5) Omega cm are obtained depending on strain and La concentration. The room temperature mobility decreases with increasing strain regardless of the sign of the strain. The observed Drude peak and Burstein-Moss shift from spectroscopic ellipsometry clearly confirm that the La addition creates a high density of free carriers in SrTiO3. First principles calculations were performed to help understand the effect of La-doping on the density of states effective mass as well as the conductivity and DC relaxation time. (C) 2014 AIP Publishing LLC.