Resolving electronic inhomogeneity in CdZnTe bulk crystal via scanning microwave impedance microscopy
Resolving electronic inhomogeneity in CdZnTe bulk crystal via scanning microwave impedance microscopy
复制标题
通过扫描微波阻抗显微镜解决 CdZnTe 块状晶体中的电子不均匀性
DOI：
10.1002/pssb.201600474
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发表时间：
2017
影响因子：
1.6
通讯作者：
Jie Wanqi
中科院分区：
文献类型：
--
作者：
Xu Yadong;Gu Yaxu;Jia Ningbo;Yu Siyuan;Han Xu;Chen Yanfeng;Jie Wanqi
利用扫描微波阻抗显微镜（MIM）对室温下生长的CdZnTe块状晶体进行了局部电子成像。在MIM图像中可以清楚地观察到嵌入CdZnTe晶体中的富Te二相（SP）颗粒。通过MIM观察到的高对比度归因于Te - SP颗粒和CdZnTe基体的介电响应和电导率之间的差异。根据均匀的MIM信号，发现Te - SP粒子内部存在均匀的相结构，进一步证实其为菱形体结构。讨论了Te - SP对响应微波强度的尺寸效应。结果表明，对于小于10 μ m的Te - SP， MIM信号基本上与畴尺寸无关。相比之下，对于大于10 μ m的Te - SP，信号幅度的线性依赖关系大致出现。此外，还研究了Te - SP周围的局部区域。在夹杂物周围有一层薄薄的过渡层，这是由Zn微偏析引起的。对于一些Te - SP粒子，粒子周围有一个宽的暗区，这是由于高浓度的扩展缺陷造成的。在Te - SP诱导的高缺陷区，由于高电子弛豫极化，微波响应较低。扫描微波阻抗显微镜（MIM）结构示意图。
Local electronic imaging using a scanning microwave impedance microscope (MIM) is performed on as‐grown CdZnTe bulk crystals at room temperature. Well‐defined Te‐rich secondary phase (SP) particles embedded in CdZnTe crystals are clearly observed in the MIM images. The high contrast observed via MIM is attributed to the discrepance between the dielectric response and conductivity of Te‐SP particles and the CdZnTe matrix. A homogeneous phase structure is found within Te‐SP particles according to the uniform MIM signal, which is further confirmed as the rhombohedral structure. The size effect of Te‐SP on the response microwave intensity is discussed. It is demonstrated that the MIM signal is essentially independent of the domain sizes for Te‐SP smaller than 10 µm. In contrast, for Te‐SP larger than 10 µm, a roughly linear size dependence of the signal amplitude appears. In addition, the local area surrounding Te‐SP is examined. A thin transition layer is observed surrounding the inclusion and is ascribed to Zn micro‐segregation. For some Te‐SP particles, a wide dark region surrounds the particle and is attributed to a high concentration of extended defects. For this Te‐SP induced higher defect region, the microwave response is lower owing to the high electron relaxation polarization.Schematic diagram depicting the scanning microwave impedance microscope (MIM) configuration.