The last crystal drawing1/9/2024 5įigure 2: Drawing of the floating zone formation.Īpplication: LHPG is such a method used in industry and material research, notably for high melting point materials, because of its flexible and cost-effective fabrication of single crystal fibers. Thus, a shared interest by many scientists includes flexible manufacturing methods to test these newly predicted materials. The 2019 Materials by Design Roadmap reports that for the first time, the number of theoretically predicted materials exceeds the number of experimentally known entries in crystallographic databases. In recent years, advances in computational materials science have led to high demand for methods to exploit synthesis of new materials. Further improvements by Martin Fejer and Robert Feigelson in 1980 helped to establish the so-called Laser-Heated Pedestal Growth (LHPG), as shown in Figure 1. A solution to this problem was presented in 1972 by John Haggerty, who used CO 2 laser radiation to create the floating zone in a fiber drawing process. 3 The floating zone technique was the preferred choice but could not be applied due to inefficient RF heating of the oxides. By the 1970s, the telecommunications industry was increasingly interested in growing single crystal oxides of small-diameter and high-purity due to their advantageous material properties for fiber optical applications. The absence of a crucible allowed the growth higher purity crystals, but of limited diameter (< 200 mm). A vertically arranged germanium rod was pulled through a localized melt zone created by an RF heating coil. However, only a few years later, in 1955, Henry Theuerer developed the first floating zone technique. As of today, over 90% of all semiconductor-based electronic devices are made from materials synthesized by Czochralski’s method. Decades later, in 1948, the American scientists Gordon Teal and John Little of Bell Labs used Czochralski’s method to grow extremely pure germanium and silicon single crystals, paving the way for modern semiconductor wafer production. 1 Later examination of the filament revealed that it was a single crystal. It is said that in 1916 the Polish chemist Jan Czochralski was investigating the crystallization of metals as he accidentally dipped his pen into molten tin instead of his inkwell and pulled out a thin tin filament. Background: As often in history, important scientific discoveries are made by accident.
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