how to power a crystal growth accelerator

Or it could be made from a powder and pressed into a form that conforms to the shape of the growing crystals. The HF absorber material could be sprayed, painted, or otherwise deposited onto an inert support such as quartz or various oxides to attach it to the reaction chamber. This allows uniform extraction of HF across large areas, thereby yielding crystalline end products that are uniform and homogeneous regardless of the shape of the precursor material or the area it occupies inside the reaction chamber.Ī wide range of materials from alkaline earth oxides to materials containing calcium, sodium, or even activated carbon can be used as HF absorbers. The solid material can be attached to the inner surface of the reaction chamber or free standing, as long as it is made to conform to the shape of the precursor at a uniform distance. The new method incorporates a solid material capable of absorbing hydrogen fluoride (HF) gas inside the reaction chamber. “We’ve developed an improved method for removing hydrogen fluoride, based on absorption, that enhances the production of high-quality crystalline products.” Wiesmann said. Also, other gases necessary to crystal growth, such as oxygen and water vapor, get extracted along with the hydrogen fluoride, and re-injecting these gases introduces more pressure problems. For one thing, you’d have to remove the gas uniformly, to avoid variations in pressure that might affect crystal growth, which becomes more difficult over larger areas.

“You might think you could just vent the accumulating gas, but such methods have proven impractical,” said Wiesmann. Hydrogen fluoride slows down the reaction that converts the precursor to the desired material, sometimes even stopping crystal growth in its tracks. But fluorine also presents a problem because it leads to the buildup of hydrogen fluoride gas.

Such crystals are typically grown from precursors deposited on substrates - for example: tapes, wires, or wafers, such as those used in the production of computer chips.Īdding fluorine to the precursors enhances the transfer of crystalline order from the substrate to the growing material. Materials with highly ordered crystalline atomic structures have enormous potential for energy-saving devices such as superconductors, which carry current with no energy loss, and high-speed electronics. Patent number 7,622,426 - could lead to more efficient production and improved performance of these materials. The invention - by Vyacheslav Solovyov and Harold Wiesmann and recently awarded U.S. Department of Energy’s (DOE) Brookhaven National Laboratory have developed a method to control the buildup of hydrogen fluoride gas during the growth of precision crystals needed for applications such as superconductors, optical devices, and microelectronics.

Vyacheslav Solovyov (left) and Harold 'Bud' Wiesmann

How to power a crystal growth accelerator