Visualizing Solution Structure at Solid-Liquid Interfaces using Three-Dimensional Fast Force Mapping

10.3791/62585 ◽  
2021 ◽  
Author(s):  
Elias Nakouzi ◽  
Sakshi Yadav ◽  
Benjamin A. Legg ◽  
Shuai Zhang ◽  
Jinhui Tao ◽  
...  
Keyword(s):  
Solution Structure ◽  
Three Dimensional ◽  
Liquid Interfaces ◽  
Force Mapping ◽  
Solid Liquid

For the Growth of 3 Inch D-Shaped GaAs Crystals by a Modified Horizontal Bridgman Process

1993 ◽  
Vol 207 (3) ◽  
pp. 185-195 ◽  
Author(s):  
M H Hsieh ◽  
C C Chieng ◽  
K H Lie ◽  
Y D Guo
Keyword(s):  
Dopant Concentration ◽  
Three Dimensional ◽  
Solidification Process ◽  
Temperature Fields ◽  
Liquid Interfaces ◽  
Axial Distribution ◽  
Mass Transfer Mechanism ◽  
Finite Volume Approach ◽  
Silicon Doped ◽  
Solid Liquid

Doped with silicon or zinc, 3 inch D-shaped GaAs crystals were grown by the modified two-temperature horizontal Bridgman (M2T-HB) technique. Then (1&10) wafers were sliced axially from the chunk of silicon-doped 3 inch GaAs crystals and chemically etched to reveal the growth striations of solid/liquid interfaces. Three-dimensional, numerical simulations of the solidification process for growing 3 inch crystals by the M2T-HB system were performed and compared with the etched (110) wafers from experiments. The heat- and mass-transfer mechanism through the melt is the combination of convection, conduction and radiation. The finite volume approach and the continuum model are employed to determine the position and shape of the interface of the solid/melt, dopant concentration and the temperature field in the crystal and melt. Two methods for computing the dopant concentration are (a) solving the transport equation of full mass concentration and (b) using the simplified model of equilibrium. The computed solidification fronts and the dopant distributions agree successfully with the experimental data, and the axial distribution of dopant concentration as well as flow and temperature fields are computed for information of the crystal quality.

Surface Functionalization Mechanisms of Enhancing Heat Transfer at Solid-Liquid Interfaces

2011 ◽  
Vol 133 (8) ◽  
Author(s):  
Javier V. Goicochea ◽  
Ming Hu ◽  
Bruno Michel ◽  
Dimos Poulikakos
Keyword(s):  
Heat Flux ◽  
Surface Functionalization ◽  
Heat Dissipation ◽  
Silica Surface ◽  
Three Dimensional ◽  
Thermal Conductance ◽  
Dynamics Simulation ◽  
Nonequilibrium Molecular Dynamics ◽  
Liquid Interfaces ◽  
Solid Liquid

Two mechanisms that enhance heat dissipation at solid-liquid interfaces are investigated from the atomistic point of view using nonequilibrium molecular dynamics simulation. The mechanisms include surface functionalization, where –OH terminated headgroups and self-assembled monolayers (SAMs) with different chain lengths are used to recondition and modify the hydrophilicity of silica surface, and vibrational matching between crystalline silica and liquid water, where three-dimensional nanopillars are grown at the interface in the direction of the heat flux with different lengths to rectify the vibrational frequencies of surface atoms. The heat dissipation is measured in terms of the thermal conductance of the solid-liquid interface and is obtained by imposing a one-dimensional heat flux along the simulation domain. A comparison with reported numerical and experimental thermal conductance measurements for similar interfaces indicates that the thermal conductance is enhanced by 1.8–3.2 times when the silica surface is reconditioned with hydrophilic groups. The enhancement is further promoted by SAMs, which results in a 20% higher thermal conductance compared with that of the fully hydroxylated silica surface. Likewise, the presence of nanopillars enhances the interface thermal conductance by 2.6 times compared with a bare surface (without nanopillars). Moreover, for different nanopillar densities, the conductance increases linearly with the length of the pillar and saturates at around 4.26 nm. Changes in the vibrational spectrum of surface atoms and water confinement effects are found to be responsible for the increase in conductance. The modification of surface vibrational states provides a tunable path to enhance heat dissipation, which can also be easily applied to other fluids and interfaces.

Surface Functionalization Mechanisms of Enhancing Heat Transfer at Solid-Liquid Interfaces

2010 ◽  
Author(s):  
Ming Hu ◽  
Javier V. Goicochea ◽  
Bruno Michel ◽  
Dimos Poulikakos
Keyword(s):  
Heat Flux ◽  
Surface Functionalization ◽  
Heat Dissipation ◽  
Silica Surface ◽  
Three Dimensional ◽  
Thermal Conductance ◽  
Point Of View ◽  
Nonequilibrium Molecular Dynamics ◽  
Liquid Interfaces ◽  
Solid Liquid

Two mechanisms that increase heat dissipation at solid-liquid interfaces are investigated from the atomistic point of view using nonequilibrium molecular dynamics (NEMD) simulation. The mechanisms include surface functionalization, where −OH terminated headgroups and self-assembled monolayers (SAMs) with different chain lengths are used to recondition and modify the hydrophilicity of silica surface, and vibrational matching between crystalline silica and liquid water, where three-dimensional quartz nanopillars are grown at the interface in the direction of the heat flux with different lengths to rectify the vibrational frequencies of quartz surface atoms. The heat dissipation is measured in terms of the interfacial thermal conductance at the solid-liquid interface, whereas the thermal conductance is obtained by imposing a one-dimensional heat flux across the simulation domain. The heat dissipation is enhanced by a factor of 2 to 3 for both fully hydroxylated and pillar modified surfaces. The SAMs enhance the overall thermal conductance between silica and water further (20% higher thermal conductance compared to the fully hydroxylated silica surface). Moreover, the modification of the vibrational states at the silica surface provides a tunable path to enhance the heat dissipation, which can also be easily applied to other fluids.

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