Effects of baffle design on fluid flow and heat transfer in ammonothermal growth of nitrides

Chen, Qi-Sheng; Pendurti, S.; Prasad, V.

doi:10.1016/j.jcrysgro.2004.02.055

Cited by 27 publications

(15 citation statements)

References 12 publications

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“…The relation between solubility and temperature will be greatly influenced by a mineralizer. Thus, Chen et al have made calculations for the ammonothermal GaN single crystal growth process when the raw material zone is (1) under the baffle (12) and (2) over the baffle (13) . They have not discussed an improvement of a real crystal growth process.…”

Section: Calculation Methodsmentioning

confidence: 99%

Numerical Simulation of Hydrothermal Autoclave for Single-Crystal Growth Process

Masuda¹,

Suzuki²,

Mikawa

et al. 2008

JTST

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Numerical simulation of the hydrothermal process for growing two-inch bulk single crystals of ZnO has been done. The autoclave is assumed to be axisymmetric. The heat transfer by natural convection is discussed for flat and funnel-shaped baffles. The funnel-shaped baffle leads to a significant increase in the flow rate between the raw material zone and the crystal growth zone. However, the temperature difference between the two zones does not become very small. Therefore, the funnel-shaped baffle is effective in the hydrothermal crystal growth process from the viewpoint of transport phenomena. The calculations show that the optimum baffle angle about 20°. Similar results are obtained when the raw material is considered as a porous medium.

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Section: Calculation Methodsmentioning

confidence: 99%

Numerical Simulation of Hydrothermal Autoclave for Single-Crystal Growth Process

Masuda¹,

Suzuki²,

Mikawa

et al. 2008

JTST

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“…Chen et al [9][10][11] investigated the ammonothermal GaN singlecrystal process by numerical simulation extensively. They studied the effects of retrograde solubility and forward solubility on the fluid flow pattern and temperature distribution around the baffle, the effect of particle size on the nutrient transport and the effects of the baffle design.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of ammonothermal growth processes of GaN crystals

Jiang

Chen

Prasad

2011

Journal of Crystal Growth

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a b s t r a c tGallium nitride (GaN) is a semiconductor material with a wide array of applications in the manufacture of blue/green light LEDs, lasers and high power electronic devices. In the ammonothermal growth, ammonia is used as a solvent instead of water as in the hydrothermal process. We modeled ammonothermal growth of GaN crystal of 1 in. size in a cylindrical high-pressure autoclave and discussed the effects of the different baffle design. We can conclude that, under the condition of forward solubility, the small opening is not in favor of the crystal growth. When the opening increases from 12% to 16%, the flow direction in the central hole changes from positive to negative. In the cases of 16% and 20% openings the flow in the autoclave exhibits a steady circulation, so the growth is stable. The transfer of raw material depends on the baffle opening and the temperature difference between growth zone and dissolving zone.

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“…The autoclave used had internal diameter of 0.932 cm and external diameter of 3.5 cm (Tem-Press MRA 138R, volume 12.5 ml). Chen et al [12] modeled the GaN growth process in an autoclave with internal diameter of 2.22 cm and external diameter of 7.62 cm (Tem-Press MRA 378R, volume 134 ml). Flow and temperature patterns inside the autoclave with baffle openings of 15% and 20% in cross-sectional area were analyzed.…”

Section: Introductionmentioning

confidence: 99%

Modeling of ammonothermal growth processes of GaN crystal in large-size pressure systems

et al. 2011

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Gallium nitride (GaN) is a wide-bandgap semiconductor material with a wide array of applications in optoelectronics and electronics. Modeling of the fluid flow and thermal fields is discussed, and simulations of velocity and volumetricflow-rate profiles in different pressure systems are shown. The nutrient is considered as a porous media bed, and the flow is simulated using the Darcy-BrinkmanForchheimer model. The resulting governing equations are solved using the finitevolume method. We analyzed the heat and mass transfer behaviors in autoclaves with diameters of 2.22, 4.44, and 10 cm. The effects of baffle design on flow pattern, and heat and mass transfer in different autoclaves are analyzed. For the research-grade autoclave with diameter of 2.22 cm, the constraint for the GaN growth is found to be the growth kinetics and the total area of seed surfaces in the case of baffle opening of 10%. For large-size pressure systems, the concentration profiles change dramatically due to stronger convection at higher Grashof numbers. The volumetric flow rates of the solvent across the baffles are calculated. Since ammonothermal growth experiments are expensive and time consuming, modeling becomes an effective tool for research and optimization of ammonothermal growth processes.

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Effects of baffle design on fluid flow and heat transfer in ammonothermal growth of nitrides

Cited by 27 publications

References 12 publications

Numerical Simulation of Hydrothermal Autoclave for Single-Crystal Growth Process

Numerical Simulation of Hydrothermal Autoclave for Single-Crystal Growth Process

Numerical simulation of ammonothermal growth processes of GaN crystals

Modeling of ammonothermal growth processes of GaN crystal in large-size pressure systems

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