Characterization of precipitates in CdTe and Cd1−xZnxTe grown by vertical Bridgman-Stockbarger technique

Shen, Jian; Aidun, D. K.; Regel, L. L.; Wilcox, William R.

doi:10.1016/0022-0248(93)90269-3

Cited by 55 publications

(27 citation statements)

References 14 publications

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“…Further, it was often observed that voids exist inside Te inclusions. 5 Such voids might have originated from the strong stress field around the Te inclusions, because the thermal expansion coefficient of Te is considerably higher than that of CZT, or by coalescence of Cd vacancies at the Te-rich secondary phase. During the migration of these large Te inclusions, the voids cannot move with the main portion of the inclusions, so leaving behind small spots that scatter the IR light.…”

Section: Methodsmentioning

confidence: 99%

Post-growth Annealing of Cadmium Zinc Telluride Crystals for Room-Temperature Radiation Detectors

Yang

Bolotnikov

Fochuk

et al. 2012

Journal of Elec Materi

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We investigated the effects of post-growth annealing on cadmium zinc telluride crystals intended for use as room-temperature radiation detectors. Annealing under Cd vapor effectively eliminated Te inclusions. The material's resistivity was lowered, and loss of Zn component was observed. Annealing under Cd + Zn vapors similarly removed Te inclusions. Furthermore, after exposure to the two vapors, we noted a change in the crystal surface morphology, i.e., formation of patterns of parallel lines. In contrast to annealing under Cd vapor alone, high resistivity was maintained after suitably controlling the Cd and Zn pressures.

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Section: Methodsmentioning

confidence: 99%

Post-growth Annealing of Cadmium Zinc Telluride Crystals for Room-Temperature Radiation Detectors

Yang

Bolotnikov

Fochuk

et al. 2012

Journal of Elec Materi

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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.…”

mentioning

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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“…Typical sizes between 10-100 nm have been determined for As precipitates in GaAs [95] and Te precipitates in CdTe [96]. Half-empty precipitates have been found by transmission electron microscopy (TEM) in GaAs [97] and CdTe [98], probably, caused by vacancy condensation in one of the sublattices accompanied by conglomeration of excess atoms of the opposite sublattice.…”

Section: Second-phase Particlesmentioning

confidence: 99%

Thermodynamics, Origin, and Control of Defects

Rudolph

2008

Crystal Growth Technology

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Characterization of precipitates in CdTe and Cd1−xZnxTe grown by vertical Bridgman-Stockbarger technique

Cited by 55 publications

References 14 publications

Post-growth Annealing of Cadmium Zinc Telluride Crystals for Room-Temperature Radiation Detectors

Post-growth Annealing of Cadmium Zinc Telluride Crystals for Room-Temperature Radiation Detectors

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

Thermodynamics, Origin, and Control of Defects

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