Overcoming Zn segregation in CdZnTe with the temperature gradient annealing

Kim, K.; Bolotnikov, A. E.; Camarda, G. S.; Hossain, Anwar; James, R. B.

doi:10.1016/j.jcrysgro.2016.02.038

Cited by 8 publications

(4 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure 7 shows that the Zn atomic fraction increases from the upper edge towards the ingot tips, except in ingot CZTF4, where the trend is the opposite. Zn is a Cd substitutional dopant, but its much lower mass allows it to be incorporated in the growth of single crystals with a Zn distribution coefficient higher than one, which leads to its segregation during growth and to an inhomogeneous atomic composition in the ingot [ 9 ].…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

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

View full text Add to dashboard Cite

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.

show abstract

Section: Resultsmentioning

confidence: 99%

“…The high crystallinity is directly related with the compound homogeneity and low amount of dislocations as well as the presence of Te precipitated/inclusions [ 8 ]. The homogeneity of the composition is also important to guarantee uniformity in electrical resistivity and energy bandgap [ 9 ].…”

Section: Introductionmentioning

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

View full text Add to dashboard Cite

show abstract

“…While basic binary CdTe assures high radiation absorption and sufficient band-gap energy, Zn is added to the material to increase the band gap and the resistivity. Despite recent progress in CZT technology [2], it suffers from several inconvenient problems: nonunity segregation coefficient of Zn in the range 1.05 to 1.6, depending on the growth method and Zn content [3]; abundant emergence of crystal defects and networks (such as subgrain boundaries); and high concentrations of Te inclusions or precipitates [4,5]. These issues result in a low yield and high cost of high-quality CZT radiation detectors, which limit their applications.…”

Section: Introductionmentioning

confidence: 99%

Charge Transport and Space-Charge Formation in Cd1−xZnxTe1−ySey Radiation De

et al. 2021

Self Cite

View full text Add to dashboard Cite

The electron-and hole-transport properties in cadmium zinc telluride selenide (CZTS) crystals are studied using a laser-induced transient-current technique with pulsed and dc bias. The internal electric field profile and velocity of surface recombination are determined by Monte Carlo simulations of electron and hole transient currents combined with a numerical solution of the driftdiffusion equation coupled with Poisson's equation. Electron and hole drift mobilities of μe = 830 cm 2 /Vs and μh = 40 cm 2 /Vs, respectively, are determined. We also develop a simple technique for evaluating surface recombination directly from measured current waveforms without the need for numerical simulation. The good quality of the prepared detector at pulsed bias, with electron-and hole-mobility-lifetime products of (μτ)e = 1.9 × 10 −3 cm 2 /V and (μτ)h = 1.4 × 10 −4 cm 2 /V, respectively, are observed. The formation of a positive space charge, originating from hole injection combined with a recombination level, is found. We observe a significant position dependence of the lifetime of electrons and holes in dc bias due to hole injection. The experiment is successfully fitted by a simple model dominated by a single deep recombination level with an energy of Et = EC − 0.73 eV; concentration of 7.3 × 10 11 cm −3 ; and electron-and hole-capture cross sections of 3.5 × 10 −14 cm 2 and 6.5 × 10 −14 cm 2 , respectively.

show abstract

“…Generally, one annealing method only contains one step. For example, in order to reduce Te inclusions, CdTe-based crystals are generally annealed under a Cd atmosphere [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Study of Detector-Grade CdMnTe:In Crystals Obtained by a Multi-Step Post-Growth Annealing Method

Chen

Liu

et al. 2018

Crystals

View full text Add to dashboard Cite

A multi-step annealing method was successfully applied to inclusions reduction and resistivity improvement of CdMnTe:In (CMT:In) single crystals with high resistivity, including a Cd atmosphere annealing step followed by a Te atmosphere annealing step. After the Cd atmosphere annealing step, the density of Te inclusions was reduced distinctly, and it could be also decreased in the subsequent step of re-annealing under Te atmosphere. Both the resistivity and IR transmittance decreased notably after Cd atmosphere annealing, whereas they increased tremendously after re-annealing under a Te atmosphere. The reduction of full-width at-half-maximum (FWHM) and the increase of the intensity of the X-ray rocking curve indicated an improvement of the crystal quality. Meanwhile, after Cd atmosphere annealing, the increase of the intensity of the (D0,X) peak and the disappearance of the (A0,X) peak in photoluminescence (PL) measurements suggested further that the crystal quality was improved. The detector performance was enhanced obviously after annealing. The higher the annealing temperature, the better the performance was. The detector fabricated by CMT:In slice (Cd atmosphere annealing at 1073 K for 240 h and Te atmosphere re-annealing at 773 K for 120 h) with 9.43% energy resolution and 1.25 × 10−3 cm2/V μτ value had the best detector performance.

show abstract

Overcoming Zn segregation in CdZnTe with the temperature gradient annealing

Cited by 8 publications

References 16 publications

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)

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)

Charge Transport and Space-Charge Formation in Cd1−xZnxTe1−ySey Radiation De

Study of Detector-Grade CdMnTe:In Crystals Obtained by a Multi-Step Post-Growth Annealing Method

Contact Info

Product

Resources

About