Photoexcited carrier dynamics of thin film Cd3As2 grown on a GaAs(111)B substrate by molecular beam epitaxy
Photoexcited carrier dynamics of thin film Cd3As2 grown on a GaAs(111)B substrate by molecular beam epitaxy
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通过分子束外延在 GaAs(111)B 衬底上生长的薄膜 Cd3As2 的光激发载流子动力学
DOI：
10.1103/physrevb.104.094302
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发表时间：
2021
影响因子：
3.7
通讯作者：
Zhang Xinhui
中科院分区：
文献类型：
--
作者：
Zhai Guihao;Ma Jialin;Wang Hailong;Ye Jialiang;Li Ting;Li Ying;Liang Gaoming;Zhao Jianhua;Wu Xiaoguang;Zhang Xinhui
拓扑狄拉克半金属由于其新颖的物理性质和在红外和太赫兹光电子器件中的技术应用而引起了人们的极大关注。研究光激发载流子的动力学特性有助于理解与其非常规能带特性密切相关的瞬态载流子占据和冷却过程。本文采用时间分辨的中红外瞬态反射率测量技术，沿着电子-极性光学（-PO）声子相互作用的理论模型，研究了衬底上外延生长的薄膜中的光激发载流子动力学。测量的光激发电子弛豫时间随探测波长的增加而增加，在30 K以上随温度的增加而增加。在双温度模型框架下的理论模型可以很好地定性描述载流子弛豫时间的温度和探测波长依赖性。此外，理论模型表明，电荷屏蔽的电子与极性光学声子的相互作用可以大大降低热载流子弛豫速率。瞬态反射率的测量结果表明，热声子效应对载流子弛豫的影响可以忽略不计。我们的研究结果为进一步了解光激发载流子的动力学行为提供了理论依据，为研制高性能的红外光电器件提供了参考。
The topological Dirac semimetalhas drawn great attention for its novel physics and technical applications in optoelectronic devices operating in the infrared and THz regimes. Exploring the photoexcited carrier dynamics inis helpful to understand the transient carrier occupation and cooling processes that are closely associated with its unconventional band characteristic. Here, the photoexcited carrier dynamics in thethin film epitaxially grown on thesubstrate was investigated by employing the time-resolved midinfrared transient reflectance measurements, along with a theoretical modeling concerning the electron-polar optical (-PO) phonon interaction. The measured photoexcited electron relaxation time ofincreases with the probe wavelength, and increases with temperature at temperatures higher than 30 K. Theoretical modeling under the framework of the two-temperature model can give qualitatively good description on both the temperature and probe wavelength dependence of the carrier relaxation time. Additionally, theoretical modeling shows that charge screening of the interaction of electrons with polar optical phonons can greatly reduce the hot carrier relaxation rate. The measured transient reflectance analyses indicate that the hot phonon effect plays a negligible role on the carrier relaxation in. Our findings provide further insight into the photoexcited carrier dynamics inand valuable reference for developing its high-performance infrared optoelectronic devices.