Single-crystal seeding

Figure 5. Acicular mordenite crystals grown at 200°C and 16 hours using the single-crystal seeds shown in Figure 2. (scanning electron micrographs courtesy of AMR Corp. Burlington, Mass.)...

The role of surfactants in promoting one-dimensional growth from single crystal seeds has been analysed computationally and this is discussed in Section 11.4 1.2 4. 

FeIn2S4 crystals were preliminary synthesized by a two-temperature method from elements of semiconductor degree of purity. The obtained crystals were reloaded into double quartz ampoules, where internal ampoule had the capillary on its bottom to provide formation of single crystal seed. After evacuating of the internal ampoule it was allocated into the second quartz ampoule of larger diameter that next was also evacuated. A quartz rod was welded to the bottom of the external ampoule as a holder. 

Float-Zone Process - In reference to solar photovoltaic cell manufacure, a method of growing a large-size, high-quality crystal whereby coils heat a polycrystalline ingot placed atop a single-crystal seed. As the coils are slowly raised the molten interface beneath the coils becomes a single crystal. 

Small amounts of well crystallized diamond were found after hydrothermal treatment of P-SiC powder at 700-750°C in the presence of diamond seed [55]. After removing silica and nondiamond carbon, small (<3pm) carbon particles of predominantly octahedral shape, thus being probably diamond, were found. They were attached to the surfaces of the single crystal seed but could be removed by intense ultrasonic treatment. Tetrahedral hillocks of etch pits appeared on the seed diamond surfaces. The hillocks always showed a faceted structure and sometimes common orientation, as expected for homoepitaxial diamond growth. 

In Fig. 1-41, if a solution is cooled carefully without a crystallization seed, the following is observed despite the fact that the saturation line has been crossed no dissolved solid crystallizes. After passing the first oversolubility curve, single crystal seeds may be observed, whilst on passing the second oversolubility curve, small crystals develop spontaneously. The area of the stable, unsaturated solution is followed by the area of the metastable, over-saturated solution between the saturation line and the second over-saturation line. It follows that the area where seeds are spontaneously formed is the area of unstable two- or multiphase systems. 

Fig. 12.12 Ideal composition profile (schematic) necessary to generate a GalnSb single-crystal seed from a binary InSb or GaSb seed.

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