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A seed crystal is a small piece of single crystal or polycrystal material from which a large crystal of typically the same material is grown in a laboratory. Used to replicate material, the use of seed crystal to promote growth avoids the otherwise slow randomness of natural crystal growth, and allows manufacture on a scale suitable for industry.
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. The process can be carried out in a horizontal or vertical orientation, and usually involves a rotating crucible/ampoule to stir the melt.
To achieve a moderate number of medium-sized crystals, a container which has a few scratches works best. Likewise, adding small previously made crystals, or seed crystals, to a crystal growing project will provide nucleating sites to the solution. The addition of only one seed crystal should result in a larger single crystal.
A precisely oriented rod-mounted seed crystal is dipped into the molten silicon. The seed crystal's rod is slowly pulled upwards and rotated simultaneously. By precisely controlling the temperature gradients, rate of pulling and speed of rotation, it is possible to extract a large, single-crystal, cylindrical ingot from the melt.
The Kyropoulos method, also known as the KY method or Kyropoulos technique, is a method of bulk crystal growth used to obtain single crystals.. The largest application of the Kyropoulos method is to grow large boules of single crystal sapphire used to produce substrates for the manufacture gallium nitride-based LEDs, and as a durable optical material.
The process can also be performed with a custom-oriented seed crystal to achieve a specific desired crystallographic orientation. Synthetic Corundum. Crystals produced by the Verneuil process are chemically and physically equivalent to their naturally occurring counterparts, and strong magnification is usually required to distinguish between ...