Laser terahertz emission microscopy revealing the local fluctuation of terahertz generation induced by Te inclusion
Laser terahertz emission microscopy revealing the local fluctuation of terahertz generation induced by Te inclusion
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激光太赫兹发射显微镜揭示了Te夹杂物引起的太赫兹产生的局部波动
DOI：
10.1063/5.0045266
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发表时间：
2021
影响因子：
4
通讯作者：
Yadong Xu
中科院分区：
文献类型：
--
作者：
Jiangpeng Dong;Kazunori Serita;Fumikazu Murakami;Iwao Kawayama;Han Sun;Binbin Zhang;Masayoshi Tonouchi;Wanqi Jie;Yadong Xu
碲化锌（ZnTe）作为一种先进的电光晶体，被广泛应用于光整流太赫兹（THz）辐射。然而，在ZnTe中产生THz的效率通常被诸如谐波产生、双光子吸收和自由载流子吸收的因素降低。在这项工作中，我们首次报告的影响，微观尺度的碲夹杂物在ZnTe的局域太赫兹发射。观察到Te夹杂物发射的异常THz时域波形持续时间超过400 ps，这归因于光电流浪涌（PS）效应。这种Te夹杂相关的太赫兹辐射被证明是一致的入射功率和偏振角的依赖性。同时，嵌入在ZnTe基质中的Te夹杂物通过激光太赫兹发射显微镜（LTEM）可视化。根据LTEM图像，揭示了载流子运动的驱动力，这归因于由Te和p-ZnTe组成的异质结场。我们的研究结果不仅提供了一个全面的了解太赫兹特性的Te夹杂物，但也提出了LTEM作为一个有前途的非接触评估方法，用于评估半导体中的体缺陷。
As a state-of-the-art electro-optical crystal, zinc telluride (ZnTe) is widely used in terahertz (THz) emission by optical rectification. However, the efficiency of THz generation in ZnTe is usually degraded by factors such as harmonic generation, two-photon absorption, and free-carrier absorption. In this work, we first report the effect of micro-scale Te inclusions in ZnTe on the local area THz emission. Unusual THz time-domain waveforms emitted from Te inclusions are observed to last longer than 400 ps, which is attributed to the photocurrent surge (PS) effect. This Te inclusion-associated THz radiation is proved consistent with the incident power and polarization angle dependences. Simultaneously, the Te inclusions embedded in the ZnTe matrix are visualized by laser THz emission microscopy (LTEM). According to the LTEM images, the driving force of the carrier movement is revealed, which is ascribed to the heterojunction field composed of Te and p-ZnTe. Our results not only afford a comprehensive understanding of the THz characteristics of Te inclusions but also put forward LTEM as a promising non-contact evaluation method for evaluating the bulk defects in semiconductors.