Te inclusion-induced electrical field perturbation in CdZnTe single crystals revealed by Kelvin probe force microscopy

Gu, Yaxu; Wang, Jie; Li, Linglong; Ye, Xu; Yang, Yaodong; Ren, Jie; Zha, Gangqiang; Wang, Tao; Xu, Lingyan; He, Yihui; Xi, Shouzhi

doi:10.1016/j.micron.2016.06.001

Cited by 6 publications

(4 citation statements)

References 31 publications

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“…and the enrichment of impurities will produce a more conductive layer at the grain boundary compared to the interior crystal. [32][33][34] As a consequence, an n-n + -n junction forms at the twin boundary, as illustrated in Fig. 5(a).…”

Section: Resultsmentioning

confidence: 99%

Twin boundary dominated electric field distribution in CdZnTe detectors

Dong

Wang

et al. 2018

Chinese Phys. B

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The performance of CdZnTe X/γ-ray detectors is strongly affected by the electric field distribution in terms of charge transport and charge collection. Factors which determine the electric field distribution are not only electric contact, but also intrinsic defects, especially grown-in twin boundaries. Here, the electric field distribution around twin boundaries is investigated in a CdZnTe bicrystal detector with a {111}-{111} twin plane using the Pockels electro-optic effect. The results of laser beam induced current pulses are also obtained by the transient current technique, and we discuss the influence of the twin boundary on the electric field evolution. These studies reveal a significant distortion of the electric field, which is attributed to the buildup of space charges at twin boundaries. Also, the position of these space charge regions depends on the polarity of the detector bias. An energy band model based on the formation of an n-n + -n junction across the twin boundary has been established to explain the observed results.

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Section: Resultsmentioning

confidence: 99%

Twin boundary dominated electric field distribution in CdZnTe detectors

Dong

Wang

et al. 2018

Chinese Phys. B

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“…The ionization of Te‐SP induced defects is suggested to be responsible for the inhomogeneous charge carrier distribution. Further analysis on potential difference identified that Te‐SP acts as a negative potential center . Therefore, the charge carrier transport properties of the devices are significantly inhibited by these Te‐SP particles and the induced defects.…”

Section: Resultsmentioning

confidence: 99%

Resolving electronic inhomogeneity in CdZnTe bulk crystal via scanning microwave impedance microscopy

Jia

et al. 2016

Phys. Status Solidi B

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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.

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“…Strains are introduced in the crystalline structure producing lattice distortions that decrease the crystalline optical transmission. This fact also degrades electrical properties [ 40 , 41 ].…”

Section: Resultsmentioning

confidence: 99%

Crystalline Quality, Composition Homogeneity, Tellurium Precipitates/Inclusions Concentration, Optical Transmission, and Energy Band Gap of Bridgman Grown Single-Crystalline Cd1−xZnxTe (0 ≤ x ≤ 0.1)

et al. 2021

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Cd1−xZnxTe (0 ≤ x ≤ 0.1) ingots were obtained by Bridgman’s method using two different speeds in order to find the optimal conditions for single-crystalline growth. Crystalline quality was studied by chemical etching, the elemental composition by wavelength dispersive spectroscopy (WDS), tellurium (Te) precipitates/inclusions concentration by differential scanning calorimetry (DSC), optical transmission by Fourier transformed infrared spectrometry (FTIR), and band gap energy (Egap) by photoluminescence (PL). It was observed that the ingots grown at a lower speed were those of the best crystalline quality, having at most three grains of different crystallographic orientation. The average dislocations density in all of them were similar and correspond to materials of good quality. EPMA results indicated that the homogeneity in the composition was excellent in the ingots central part. The concentration of Te precipitates/inclusions in all ingots was below the instrument (DSC) detection limit, 0.25% wt/wt. In the case of wafers from Cd0.96Zn0.04Te and Cd0.90Zn0.10Te ingots, the optical transmission was better than that of commercial materials and varied between 60% and 70%, while for pure CdTe, the transmission range was between 50% and 55%, the latter being decreased by the presence of Te precipitates/inclusions. The band gap energy Eg of different wafers was experimentally obtained by PL measurements at 76 K. We observed that Eg increased with the Zn concentration of the wafers, following a linear regression comparable to those proposed in the literature, and consistent with the results obtained with other techniques.

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Te inclusion-induced electrical field perturbation in CdZnTe single crystals revealed by Kelvin probe force microscopy

Cited by 6 publications

References 31 publications

Twin boundary dominated electric field distribution in CdZnTe detectors

Twin boundary dominated electric field distribution in CdZnTe detectors

Resolving electronic inhomogeneity in CdZnTe bulk crystal via scanning microwave impedance microscopy

Crystalline Quality, Composition Homogeneity, Tellurium Precipitates/Inclusions Concentration, Optical Transmission, and Energy Band Gap of Bridgman Grown Single-Crystalline Cd1−xZnxTe (0 ≤ x ≤ 0.1)

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