Effect of accelerated crucible rotation on the segregation of impurities in vertical Bridgman growth of multi-crystalline silicon

Bellmann, M.P.; Meese, Ernst A.; Arnberg, L.

doi:10.1016/j.jcrysgro.2010.10.069

Cited by 24 publications

(13 citation statements)

References 19 publications

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“…The melt flow inside the crucible is governed by interaction of several driving forces i.e. buoyancy, thermocapillary, and forced convection (crystal and crucible rotation) [2][3][4]. These forces should be balanced in order to form the melt/crystal interface shape as flat as possible.…”

Section: Introductionmentioning

confidence: 99%

Analysis of W-shape melt/crystal interface formation in Czochralski silicon crystal growth

Noghabi

Jomâa

M’Hamdi

2013

Journal of Crystal Growth

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Section: Introductionmentioning

confidence: 99%

Analysis of W-shape melt/crystal interface formation in Czochralski silicon crystal growth

Noghabi

Jomâa

M’Hamdi

2013

Journal of Crystal Growth

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“…The numerical model, operating system and physical material properties are the same as from our previous studies, where we have studied the effect of thermal convection [17] and the effect of ACRT [3] on the impurity segregation in mc-silicon.…”

Section: Numerical Approachmentioning

confidence: 99%

“…The evaporation of oxygen from the free melt surface is not modeled explicitly, instead it is considered by a segregation coefficient of k 0 41 [21]. Thermophysical properties used in the simulation are taken from our previous studies [17,3] and species transport properties are shown in Table 1. The heat of fusion was set to z ¼ 1:8 Â 10 6 J kg À1 and the dynamic viscosity to m ¼ 8:8 Â 10 À4 kg ðm À1 s À1 Þ.…”

Section: Numerical Approachmentioning

confidence: 99%

“…One of the solutions is to control the segregation of impurities by forcing the melt convection externally, e.g. by traveling magnetic fields [1,2] or by axial rotation of a cylindrical crucible [3,4]. The steady crucible rotation technique is a versatile tool to control the fluid flow in a crucible, e.g.…”

Section: Introductionmentioning

confidence: 99%

“…However, the non-rotating case was not studied. Recently, we have performed numerical simulations for the same growth system, applying the accelerated crucible rotation technique (ACRT), which led to an increased radial segregation as thermal buoyancy convection was suppressed [3].…”

Section: Introductionmentioning

confidence: 99%

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Effect of steady crucible rotation on the segregation of impurities in vertical Bridgman growth of multi-crystalline silicon

Bellmann

Meese

2011

Journal of Crystal Growth

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a b s t r a c tWe have performed axisymmetric, transient simulations of the vertical Bridgman growth of multicrystalline (mc) silicon to study the effect of the steady crucible rotation on the melt flow and impurity segregation. A solute transport model has been applied to predict the final segregation pattern of impurities in a circular ingot. Imposing rotation rates of 1-5 rpm on the system makes radial segregation much worse compared to the non-rotating case. Low rotation rates at 1-2 rpm increase radial segregation in the first half period of solidification, whereas at rotation rates above the effect is insignificantly small. Contrary behavior was observed for the second half period of solidification. Here radial segregation is increased at high rotation rates from 3 to 5 rpm with small impact at 1-2 rpm.

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Orthorhombic Non‐Perovskite CsPbI₃ Microwires for Stable High‐Resolution X‐Ray Detectors

Kundu

Richtsmeier

Hart

et al. 2022

Advanced Optical Materials

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Direct conversion X-ray detectors operate by directly converting X-ray photons into an electrical signal, while indirect conversion detectors (also called scintillators) first convert X-ray photons to visible light. Subsequently, this light is converted to an electrical signal using visible light detectors. Direct conversion detectors are simpler in configuration and offer higher spatial resolution than scintillators. [2] Among traditional semiconductors, amorphous selenium (a-Se), [3] and Cd 1−x Zn x Te (CZT, x < 20%)-based materials [4] dominate the market of commercial X-ray detectors. a-Se has a low device dark current and stable device performance; however, it possesses low X-ray absorptivity. On the other hand, CZT offers excellent absorptivity, but requires high-temperature processing conditions (>900 °C), [5] and suffers from structural imperfections [5,6] and compositional inhomogeneity. [6,7] These limitations demand the development of novel semiconductors for direct X-ray detectors.Solution-processed metal halide perovskites have recently emerged as a family of unique semiconductors for X-ray detectors. [2b,8] Due to their elemental constitution of heavy atoms such as lead and iodine, metal halide perovskites have a high X-ray attenuation coefficient. [2b,8b,9] However, conventional perovskites suffer from long-term instability, and high dark current (determines noise level). [10] Early diagnoses of diseases requires high spatial resolution, which is measured by recording the resolving power of a line-pair (lp) phantom. [11] For radiology, a minimum spatial resolution of 5.7 lp mm −1 is required for adequate resolution of small objects. [12] Imaging becomes more challenging when it comes to mammographic applications, where a resolution of 10 lp mm −1 is needed to resolve small microcalcifications. [13] Unfortunately, conventional direct conversion X-ray detectors have low resolution as they are integrated into transistor arrays with limited pixel dimensions. [14] Here we report a strategy to grow aligned orthorhombic δ-CsPbI 3 microwires offering one of the highest X-ray absorption coefficients. The crystals show a record-low dark current density of 12 pA mm −2 under 600 V mm −1 electric field. A Schottky junction with δ-CsPbI 3 is able to sense dose rates as low as 33.3 nGy air s −1 . We also show an X-ray spatial resolution of ≈12.4 lp mm −1 , which is one of the highest values reported to date (Table S1, Supporting Information). The fabricated X-ray detectors are used widely, but they suffer from short operational stability and insufficient absorptivity of X-ray photons. Here, a strategy for roomtemperature, solution-grown δ-CsPbI 3 monocrystalline microwires exhibiting one of the highest linear X-ray absorption coefficients among known semiconductors is reported. In a metal-semiconductor-metal architecture, δ-CsPbI 3 demonstrates one of the lowest detectable X-ray dose rates at 33.3 nGy air s −1 , enabled by its exceptionally low dark current density of 12 pA mm −2 . The detector remains stab...

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Effect of accelerated crucible rotation on the segregation of impurities in vertical Bridgman growth of multi-crystalline silicon

Cited by 24 publications

References 19 publications

Analysis of W-shape melt/crystal interface formation in Czochralski silicon crystal growth

Analysis of W-shape melt/crystal interface formation in Czochralski silicon crystal growth

Effect of steady crucible rotation on the segregation of impurities in vertical Bridgman growth of multi-crystalline silicon

Orthorhombic Non‐Perovskite CsPbI₃ Microwires for Stable High‐Resolution X‐Ray Detectors

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Effect of accelerated crucible rotation on the segregation of impurities in vertical Bridgman growth of multi-crystalline silicon

Cited by 24 publications

References 19 publications

Analysis of W-shape melt/crystal interface formation in Czochralski silicon crystal growth

Analysis of W-shape melt/crystal interface formation in Czochralski silicon crystal growth

Effect of steady crucible rotation on the segregation of impurities in vertical Bridgman growth of multi-crystalline silicon

Orthorhombic Non‐Perovskite CsPbI3 Microwires for Stable High‐Resolution X‐Ray Detectors

Contact Info

Product

Resources

About

Orthorhombic Non‐Perovskite CsPbI₃ Microwires for Stable High‐Resolution X‐Ray Detectors