Transient photoconductivity and photo-excited carrier dynamics in (Bi1-xInx)2Se3 thin films
Transient photoconductivity and photo-excited carrier dynamics in (Bi1-xInx)2Se3 thin films
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DOI：
10.1117/12.2546692
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发表时间：
2020-02
影响因子：
4
通讯作者：
Teng Shi;K. Kushnir;Zhengtianye Wang;S. Law;L. Titova
中科院分区：
文献类型：
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作者：
Teng Shi;K. Kushnir;Zhengtianye Wang;S. Law;L. Titova
我们使用时间分辨太赫兹光谱研究微观电导率和光生载流子动力学在MBE生长的100 nm厚的（Bi 1-xInx）2Se 3薄膜与铟浓度从x=0到x=0.5变化。与x=0.25和x=0.50的膜相比，Bi 2Se 3中的本征和光致电导率都显著更高，载流子不受孪晶畴界的约束，并表现出1100 cm 2/Vs的高迁移率。我们发现，引入浓度为x=0.25和更高的铟，高于拓扑到平凡转变的阈值，将本征和光诱导电导率抑制超过一个数量级，并降低光激发载流子的寿命。这些研究结果表明，控制铟浓度在（Bi 1-xInx）2Se 3薄膜提供了一种途径，设计（Bi 1- xInx）2Se 3薄膜具有所需的性能，用于高速光电器件。
We use time-resolved THz spectroscopy to study microscopic conductivity and photoinduced carrier dynamics in MBE-grown 100 nm thick (Bi1-xInx)2Se3 thin films with indium concentration varying from x=0 to x=0.5. Both intrinsic and photoinduced conductivity in Bi2Se3 is significantly higher compared to the films with x=0.25 and x=0.50, with carriers that are not constrained by the twin domain boundaries and exhibit high mobility of 1100 cm2/Vs. We find that introducing indium with concentration of x=0.25 and higher, above the threshold for a topological to trivial transition, suppresses both intrinsic and photoinduced conductivity by over an order of magnitude and reduces the lifetime of photoexcited carriers. These findings demonstrate that controlling indium concentration in (Bi1-xInx)2Se3 films provides an avenue to design (Bi1- xInx)2Se3 films with desired properties for high-speed optoelectronic devices.