Single crystal

Single Crystal

	Email		Print
	Bookmark		Link

Single crystal

A single crystal, also called a monocrystal, is a crystal

Crystal

A crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions....
line solid

Solid

Discussion

Ask a question about 'Single crystal'

Start a new discussion about 'Single crystal'

Answer questions from other users

Full Discussion Forum

Encyclopedia

A single crystal, also called a monocrystal, is a crystal

Crystal

Solid

A solid object is in the states of matter characterized by resistance to deformation and changes of volume. In other words, it has high values both of Young's modulus and of shear modulus; this contrasts e.g....
in which the crystal lattice of the entire sample is continuous and unbroken to the edges of the sample, with no grain boundaries. The opposite of a single crystal sample is an amorphous structure where the atomic position is limited to short range order only. In between the two extremes exist polycrystalline
Polycrystalline

Polycrystalline materials are solids that are composed of many crystallites of varying size and orientation. The variation in direction can be random or directed, possibly due to growth and processing conditions....
and paracrystalline
Paracrystalline

Paracrystalline materials are defined as having short and medium range ordering in their lattice but lacking long range order..Ordering is the regularity in which atoms appear in a predictable lattice, as measured from one point....
phases, which are made up of a number of smaller crystals known as crystallite
Crystallite

A crystallite is a domain of solid-state matter that has the same structure as a single crystal. Metallurgy often refer to crystallites as "grains"....
s. Because of a variety of entropic

Entropy

In many branches of science, entropy is a measure of the disorder of a system. The concept of entropy is particularly notable as it is applied across physics, information theory and mathematics....
effects on the microstructure of solids, including the distorting effects of impurities

Impurity

Impurities are substances inside a confined amount of liquid, gas, or solid, which differ from the chemical composition of the material or compound....
and the mobility of crystallographic defect

Crystallographic defect

Crystalline solids have a very regular atomic structure: that is, the local positions of atoms with respect to each other are repeated at the atomic scale....
s and dislocation

Dislocation

In materials science, a dislocation is a crystallographic defect, or irregularity, within a crystal structure. The presence of dislocations strongly influences many of the properties of materials....
s, single crystals of meaningful size are exceedingly rare in nature, and can also be difficult to produce in the laboratory under controlled conditions (see also recrystallisation).

Because grain boundaries

Grain boundary

A grain boundary is the interface between two Crystallite in a polycrystalline material. Grain boundaries disrupt the motion of dislocations through a material, so reducing crystallite size is a common way to improve strength, as described by the Hall-Petch relationship....
can have significant effects on the physical and electrical properties of a material, single crystals are of interest to industry, and have important industrial applications. The most notable of these is the use of single crystal silicon

Silicon

Silicon is the most common metalloid. It is a chemical element, which has the symbol Si and atomic number 14. The atomic mass is 28.0855....
in the fabrication of semiconductors. On the quantum

Quantum mechanics

Quantum mechanics is a set of principles underlying the most fundamental known description of all physical systems at the microscopic scale . Notable amongst these principles are both a dual wave-like and particle-like behavior of matter and radiation, and prediction of probabilities in situations where classical physics predicts certaintie...
scale that microprocessor

Microprocessor

A microprocessor incorporates most or all of the functions of a central processing unit on a single integrated circuit . The first microprocessors emerged in the early 1970s and were used for electronic calculators, using Binary-coded decimal arithmetic on 4-bit Word ....
s operate on, the presence of grain boundaries would have a significant impact on the functionality of field effect transistor

Field effect transistor

The field-effect transistor is a type of transistor that relies on an electric field to control the shape and hence the electrical conductivity of a channel of one type of charge carrier in a semiconductor material....
s by altering local electrical properties. Therefore, microprocessor fabricators have invested heavily in facilities to produce large single crystals of silicon.

Fabrication of single crystals [as an example single crystalline silicon] usually involves the building of a crystal layer by layer of atoms. Techniques to produce large single crystals (boules

Boule (crystal)

A boule is a single crystal ingot produced by synthetic means. A boule of silicon is the starting material for most of the integrated circuits used today....
) include slowly drawing a rotating "seed crystal

Seed crystal

A seed crystal is a small piece of single crystal material from which a large crystal of the same material typically is to be grown. The large crystal can be grown by dipping the seed into a supersaturated solution, into molten material that is then cooled, or by growth on the seed face by passing vapor of the material to be grown over it....
" in a molten bath of feeder material [polycrystalline silicon](as in the Czochralski process

Czochralski process

The Czochralski process is a method of crystal growth used to obtain single crystals of semiconductors , metals , salts, and synthetic gemstones....
and the Bridgeman technique

Bridgeman technique

The Bridgman-Stockbarger technique is a method of growing single crystal ingots or boule .The method involves heating polycrystalline material in a container above its melting point and slowly cooling it from one end where a seed crystal is located....
). The feeder polycrystalline silicon is the purest material in the world. It is grown in rods and then melted for the formation of the single crystalline Czochralski and Bridgeman crystals.

An entirely different technology to create single crystalline materials is called epitaxy. This process deposits micrometre layers of the same or different materials on the surface of an existing single crystal.

Uses

Monocrystals of silicon
Silicon

Silicon is the most common metalloid. It is a chemical element, which has the symbol Si and atomic number 14. The atomic mass is 28.0855....
and other semiconductor
Semiconductor

A semiconductor is a material that has electrical conductivity between those of a Electrical conductor and an electrical insulation; it can vary over that wide range either permanently or dynamically....
s are important for manufacture of integrated circuit
Integrated circuit

In electronics, an integrated circuit is a miniaturized electronic circuit that has been manufactured in the surface of a thin Wafer of semiconductor material....
s.
Monocrystalline silicon photovoltaic cells have superior performance characteristics and higher price to chemically identical polycrystalline solar cell
Solar cell

A solar cell or photovoltaic cell is a device that converts sunlight directly into electricity by the photovoltaic effect. Sometimes the term solar cell is reserved for devices intended specifically to capture energy from sunlight, while the term photovoltaic cell is used when the source is unspecified....
s.
Monocrystals of sapphire
Sapphire

Sapphire refers to gem varieties of the mineral corundum, an aluminium oxide , when it is a color other than red, in which case the gem would instead be a ruby....
and other materials are used for laser
Laser

A laser is a device that emits light through a process called stimulated emission. The term laser is an acronym for light amplification by stimulated emission of radiation....
s and nonlinear optics
Nonlinear optics

Nonlinear optics is the branch of optics that describes the behaviour of light in nonlinear media, that is, media in which the dielectric polarization P responds nonlinearly to the electric field E of the light....
.
Monocrystals of fluorite
Fluorite

Fluorite is a mineral composed of calcium fluoride, CalciumFluorine. It is an Cubic mineral with a cubic habit, though octahedral and more complex isometric forms are not uncommon....
are sometimes used in the objective lenses of apochromat
Apochromat

An apochromat, or apochromatic lens , is a Photographic lens or other Lens that has better color correction than the much more common achromat lenses....
ic refracting telescopes.
Monocrystals of metals, especially superalloy
Superalloy

A superalloy, or high-performance alloy, is an alloy that exhibits excellent mechanical strength and Creep resistance at high temperatures, good surface stability, and corrosion and oxidation resistance....
s, are used for their special mechanical properties. Turbine
Turbine

A turbine is a rotary engine that extracts energy from a fluid flow. Claude Burdin coined the term from the Latin turbo, or vortex, during an 1828 engineering competition....
blades of some gas turbine
Gas turbine

A gas turbine, also called a combustion turbine, is a rotary engine that extracts energy from a flow of combustion gas. It has an upstream compressor coupled to a downstream turbine, and a combustion chamber in-between....
s are made of single crystal cast
Casting

In metalworking, casting involves pouring a liquid metal into a Mold_, which contains a hollow cavity of the desired shape, and then is allowed to solidify....
superalloy
Superalloy

A superalloy, or high-performance alloy, is an alloy that exhibits excellent mechanical strength and Creep resistance at high temperatures, good surface stability, and corrosion and oxidation resistance....
.
Monocrystals of copper (crystalline copper
Crystalline copper

Single Crystal Copper is a subtype of high purity copper metals. Other types include electrolytic copper, which however does not achieve same purity values as crystalline copper....
) are used for fine crystalline powders and hi tech wires.
Monocrystaline superconductors have superior performance characteristics to chemically identical polycrystaline superconductors.
The detailed study of the Crystal structure
Crystal structure

In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. A crystal structure is composed of a motif, a set of atoms arranged in a particular way, and a lattice....
of a material by Bragg diffraction
Bragg diffraction

Bragg diffraction was first proposed by William Lawrence Bragg and William Henry Bragg in 1913 in response to their discovery that crystalline solids produced surprising patterns of reflected X-rays ....
techniques is much easier with monocrystals. They may be grown for this purpose, even when the material is otherwise only needed in polycrystalline
Polycrystalline

Polycrystalline materials are solids that are composed of many crystallites of varying size and orientation. The variation in direction can be random or directed, possibly due to growth and processing conditions....
form.

Single crystal

Uses

See also

Further reading