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Zone melting (or zone refining, or floating-zone method, or floating-zone technique) is a group of similar methods of purifying crystals, in which a narrow region of a crystal is melted, and this molten zone is moved along the crystal. The molten region melts impure solid at its forward edge and leaves a wake of purer material solidified behind ...
The molten zone carries the impurities away with it and hence reduces impurity concentration (most impurities are more soluble in the melt than the crystal). Specialized doping techniques like core doping, pill doping, gas doping and neutron transmutation doping are used to incorporate a uniform concentration of desirable impurity.
Impurity levels of a few parts per million had previously been considered excellent; Pfann's technique improved on this by factors of over 1,000.". [2]: 199 In 1952, Pfann published the revelatory article "Principles of Zone-Melting" in the Transactions of the American Institute of Mining, Metallurgical, and Petroleum Engineers. [5]
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.
The Bridgman–Stockbarger method, or Bridgman–Stockbarger technique, is named after physicist Percy Williams Bridgman (1882–1961) and physicist Donald C. Stockbarger (1895–1952). The method includes two similar but distinct techniques primarily used for growing boules (single-crystal ingots), but which can be used for solidifying ...
Fractional freezing is a process used in process engineering and chemistry to separate substances with different melting points. It can be done by partial melting of a solid, for example in zone refining of silicon or metals, or by partial crystallization of a liquid, as in freeze distillation, also called normal freezing or progressive freezing.
The Getty Center, perched on a hill above the much-traveled 405 freeway, is a 30-minute drive away (in normal conditions) and out of the immediate fire zone, was also closed through Monday.
Zone refining techniques have led to the production of crystalline germanium for semiconductors that has an impurity of only one part in 10 10, [37] making it one of the purest materials ever obtained. [38]