Study of impurity segregation, crystallinity, and detector performance of melt-grown cadmium zinc telluride crystals

Schieber, M.; Schlesinger, T. E.; James, R. B.; Hermon, H.; Yoon, Hyoseok; Goorsky, Mark S.

doi:10.1016/s0022-0248(01)02314-4

Cited by 81 publications

(55 citation statements)

References 24 publications

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“…Consequently, the concentrations of these defects should increase to the end of the crystal growth due to prevailing Cd evaporation from the melt [29]. While Teed is a deep donor with an electronic There are frequent assertions in the literature that the DoWAoX ratio is more than unity in spectroscopic-grade CZT [2]. The concentration of shallow-level impurities invariably is much greater than that of the deep ones; thus, the DoWAoX ratio more precisely reflects the deviation from stoichiometry.…”

Section: Resultsmentioning

confidence: 99%

Distribution of zinc, resistivity, and photosensitivity in a vertical Bridgman grown Cd1−xZnxTe ingot

Babentsov¹,

Franc²,

Fauler³

et al. 2008

Journal of Crystal Growth

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We present the results of a comprehensive study of distribution of zinc, resistivity, and photosensitivity in a Cdl,Zn,Te ingot grown by the Vertical Bridgman method. We used several complementary methods, viz., glow discharge mass spectroscopy, photoluminescence-, resistivity-, and photosensitivity-mapping, along with photo-induced current transient spectroscopy to characterize the material. We identified electronic levels in the band-gap responsible for compensation, recombination, and photosensitivity.

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Section: Resultsmentioning

confidence: 99%

Distribution of zinc, resistivity, and photosensitivity in a vertical Bridgman grown Cd1−xZnxTe ingot

Babentsov¹,

Franc²,

Fauler³

et al. 2008

Journal of Crystal Growth

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“…1, 2 Over the last decade, the methods for growing high quality CZT have improved the quality of the produced crystals however there are material features that can influence the performance of these materials as radiation detectors. The presence of structural heterogeneities within the crystals, such as twinning, pipes, grain boundaries (polycrystallinity), and secondary phases (SPs) [3][4][5][6][7][8][9][10][11] can have an impact on the detector performance. There is considerable need for reliable and reproducible characterization methods for the measurement of crystal quality.…”

Section: Introductionmentioning

confidence: 99%

AFM Characterization of Raman Laser-Induced Damage on CdZnTe Crystal Surfaces

Teague

Hawkins

Duff

et al. 2009

Journal of Elec Materi

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IntroductionHigh quality CdZnTe (or CZT) crystals have the potential for use in room temperature gamma-ray and X-ray spectrometers. 1, 2 Over the last decade, the methods for growing high quality CZT have improved the quality of the produced crystals however there are material features that can influence the performance of these materials as radiation detectors. The presence of structural heterogeneities within the crystals, such as twinning, pipes, grain boundaries (polycrystallinity), and secondary phases (SPs) [3][4][5][6][7][8][9][10][11] can have an impact on the detector performance. There is considerable need for reliable and reproducible characterization methods for the measurement of crystal quality. With improvements in material characterization and synthesis, these crystals may become suitable for widespread use in gamma radiation detection.Characterization techniques currently utilized to test for quality and/or to predict performance of the crystal as a gamma-ray detector include infrared (IR) transmission imaging, synchrotron X-ray topography, photoluminescence spectroscopy, transmission electron microscopy (TEM), atomic force microscopy (AFM) and Raman spectroscopy. 1,6,7,[12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] In some cases, damage caused by characterization methods can have deleterious effects on the crystal performance. The availability of non-destructive analysis techniques is essential to validate a crystal's quality and its ability to be used for either qualitative or quantitative gamma-ray or Xray detection. The work presented herein discusses the damage that occurs during characterization of the CZT surface by a laser during Raman spectroscopy, even at minimal laser powers.Previous Raman studies have shown that the localized annealing from tightly focused, low powered lasers results in areas of higher Te concentration on the CZT surface. 16 This type of laser damage on the surface resulted in decreased detector performance which was most likely due to increased leakage current caused by areas of higher Te concentration. In this study, AFM was used to characterize the extent of damage to the CZT crystal surface following exposure to a Raman laser. AFM data reveal localized surface damage and increased conductivity in the areas exposed to the Raman laser beam. Materials and MethodsTwo different CZT crystals (CZT3-7-4 and 3-7-8) were used in this study and were obtained from Yinnel Tech (South Bend, IN). They were grown by the modified vertical Bridgman (MVB) method 27 and are composed of ~ 10% Zn content (Cd 1-x Zn x Te, with x=0.1).Both faces of the crystal were finely polished with a series of alumina grit sizes; the finest of which was 0.05 µm.CZT3-7-4 was identified as a moderate performer for gamma-ray spectrometry using an 241 Am source (Figure 1). Both the Cd-terminating face and the Te-terminating face of this crystal were exposed to an Argon ion laser (514.5 nm) in a Raman microscope system. Using the Raman laser, a series of highly damaged fiducial marks (~20 ...

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“…Because of their working potential at room temperature, CdZnTe alloys are very important for the nuclear detectors. [9][10][11][12][13][14][15] Zn x Cd 1-x Te crystals that can be used to develop X-Ray and γ-Ray detectors, to product optoelectronic devices and solar cells which operate in blue-green spectral region, are very important materials. [16][17][18] Due to the fact that it has energy band gap in 1-30 µm adjustable ranges and its big optical coefficients which maintain high quantum efficiency, HgCdTe ternary alloy is an ideal infrared detector material.…”

Section: Introductionmentioning

confidence: 99%

Investigation of structural, electronic, elastic and optical properties of Cd1-x-yZnxHgyTe alloys

Tamer

2016

AIP Advances

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Structural, optical and electronic properties and elastic constants of Cd1-x-yZnx HgyTe alloys have been studied by employing the commercial code Castep based on density functional theory. The generalized gradient approximation and local density approximation were utilized as exchange correlation. Using elastic constants for compounds, bulk modulus, band gap, Fermi energy and Kramers–Kronig relations, dielectric constants and the refractive index have been found through calculations. Apart from these, X-ray measurements revealed elastic constants and Vegard’s law. It is seen that results obtained from theory and experiments are all in agreement.

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Study of impurity segregation, crystallinity, and detector performance of melt-grown cadmium zinc telluride crystals

Cited by 81 publications

References 24 publications

Distribution of zinc, resistivity, and photosensitivity in a vertical Bridgman grown Cd1−xZnxTe ingot

Distribution of zinc, resistivity, and photosensitivity in a vertical Bridgman grown Cd1−xZnxTe ingot

AFM Characterization of Raman Laser-Induced Damage on CdZnTe Crystal Surfaces

Investigation of structural, electronic, elastic and optical properties of Cd1-x-yZnxHgyTe alloys

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