Thin Films
A thin film is a layer of material ranging from fractions of a nanometer (monolayer) to several micrometers in thickness. Electronic semiconductor devices and optical coatings are the main applications benefiting from thin-film construction.
A familiar application of thin films is the household mirror, which typically has a thin metal coating on the back of a sheet of glass to form a reflective interface. The process of silvering was once commonly used to produce mirrors. A very-thin-film coating (less than a nanometer thick) is used to produce two-way mirrors.
The performance of optical coatings (e.g. antireflective, or AR, coatings) are typically enhanced when the thin-film coating consists of multiple layers having varying thicknesses and refractive indices. Similarly, a periodic structure of alternating thin films of different materials may collectively form a so-called superlattice which exploits the phenomenon of quantum confinement by restricting electronic phenomena to two-dimensions.
Work is being done with ferromagnetic and ferroelectric thin films for use as computer memory. It is also being applied to pharmaceuticals, via thin-film drug delivery. Thin-films are used to produce thin-film batteries. Thin films are also used in dye-sensitized solar cells.
Ceramic thin films are in wide use. The relatively high hardness and inertness of ceramic materials make this type of thin coating of interest for protection of substrate materials against corrosion, oxidation and wear. In particular, the use of such coatings on cutting tools can extend the life of these items by several orders of magnitude.
Research is being done on a new class of thin-film inorganic oxide materials, called amorphous heavy-metal cation multicomponent oxides, which could be used to make transparent transistors that are inexpensive, stable, and environmentally benign.
Read more about Thin Films: Deposition, Thin-film Photovoltaic Cells, Thin-film Batteries, See Also
Famous quotes containing the words thin and/or films:
“Art can never match the luxury and superfluity of Nature. In the former all is seen; it cannot afford concealed wealth, and is niggardly in comparison; but Nature, even when she is scant and thin outwardly, satisfies us still by the assurance of a certain generosity at the roots.”
—Henry David Thoreau (1817–1862)
“Right now I think censorship is necessary; the things they’re doing and saying in films right now just shouldn’t be allowed. There’s no dignity anymore and I think that’s very important.”
—Mae West (1892–1980)