Monokrystaller

Monokrystaller, or single crystals, are solids in which the crystal lattice is continuous and unbroken throughout the entire sample, lacking grain boundaries. The absence of grain boundaries gives uniform crystallographic orientation and often anisotropic properties, as well as high purity. These characteristics make single crystals especially valuable in electronics, optics, and precision engineering.

Single crystals are produced by controlled crystallization from melts or solutions. Common growth methods include the Czochralski process, in which a seed crystal is dipped into a melt and slowly withdrawn while rotating; the Bridgman-Stockbarger method, which uses a moving temperature gradient to promote directional solidification; and the floating-zone technique, which passes a molten zone along a rod without a crucible. For some materials, solution growth or chemical vapor transport is used. The goal of these techniques is to minimize the formation of grain boundaries and manage defects.

Materials commonly grown as monocrystals include silicon and germanium for electronics, quartz for timing and optics, sapphire (aluminum oxide) for durable optical components, and diamond for extreme hardness and thermal performance. The crystallographic orientation influences properties such as electrical conductivity, refractive index, and mechanical response, leading to anisotropy. Defects like dislocations, vacancies, or inclusions can still occur and affect performance.

Applications of single crystals span semiconductors (integrated circuits, LEDs), photovoltaic cells, optical components (lenses, waveguides, lasers), quartz resonators, and specialized engineering tools. Their production is technically demanding and costly, and crystal size and quality are often limited by growth conditions and contamination control.