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The growth of a crystal through direct adsorption of a gas phase on to a solid surface is generally very slow. The VLS mechanism circumvents this by introducing a catalytic liquid alloy phase which can rapidly adsorb a vapor to supersaturation levels, and from which crystal growth can subsequently occur from nucleated seeds at the liquid ...
The Czochralski method, also Czochralski technique or Czochralski process, is a method of crystal growth used to obtain single crystals of semiconductors (e.g. silicon, germanium and gallium arsenide), metals (e.g. palladium, platinum, silver, gold), salts and synthetic gemstones.
Time-lapse of growth of a citric acid crystal. The video covers an area of 2.0 by 1.5 mm and was captured over 7.2 min. The crystallization process consists of two major events, nucleation and crystal growth which are driven by thermodynamic properties as well as chemical properties.
For perceptible growth rates, this mechanism requires a finite driving force (or degree of supercooling) in order to lower the nucleation barrier sufficiently for nucleation to occur by means of thermal fluctuations. [5] In the theory of crystal growth from the melt, Burton and Cabrera have distinguished between two major mechanisms: [6] [7] [8]
Crystal growth is achieved by the further addition of folded polymer chain segments and only occurs for temperatures below the melting temperature T m and above the glass transition temperature T g. Higher temperatures destroy the molecular arrangement and below the glass transition temperature, the movement of molecular chains is frozen. [ 6 ]
Cocrystals are typically generated through slow evaporation of solutions of the two components. This approach has been successful with molecules of complementary hydrogen bonding properties, in which case cocrystallization is likely to be thermodynamically favored. [11] Many other methods exist in order to produce cocrystals.
Molecular-beam epitaxy (MBE) is an epitaxy method for thin-film deposition of single crystals. MBE is widely used in the manufacture of semiconductor devices , including transistors . [ 1 ] MBE is used to make diodes and MOSFETs (MOS field-effect transistors ) at microwave frequencies, and to manufacture the lasers used to read optical discs ...
The methods involve heating polycrystalline material above its melting point and slowly cooling it from one end of its container, where a seed crystal is located. A single crystal of the same crystallographic orientation as the seed material is grown on the seed and is progressively formed along the length of the container.