Thin films are thin material layers ranging from fractions of a nanometre to several micrometres in thickness. Electronic semiconductor devices and optical coatings are the main applications benefiting from thin film construction.

Work is being done with ferromagnetic 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.^[1]

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 oxide, which could be used to make transparent transistors that are inexpensive, stable, and environmentally benign.^[2]

Thin-films are applied to surfaces using one of many techniques of thin-film deposition.

Thin-film technologies are also being developed as a means of substantially reducing the cost of photovoltaic (PV) systems. The rationale for this is that thin-film modules are expected to be cheaper to manufacture owing to their reduced material costs, energy costs, handling costs and capital costs, specially represented in the used of printed electronics processes.

Thin-films solar cells consist of plastic or other substrates coated with silicon (i.e. amorphous silicon) or other photovoltaic material.

These technologies face major technical hurdles. Laboratory tests have shown efficiencies of up to 19.9 percent for CIGS cells, compared with a record of about 16.5 percent for cadmium telluride. But the reality outside of the labs (commercial photovoltaic panels) has been different. So far, First Solar has reached average cell efficiencies of 10.6 percent.^[3]

Light-absorbing materials in thin-film photovoltaic cells are:

• Cadmium telluride photovoltaics
• Copper indium gallium selenide
• Dye
• Organic materials.
• Silicon:
  • Amorphous silicon and nanocrystalline silicon or microcrystalline silicon (that can be combined in micromorphous silicon).
  • Black silicon

• Ellipsometry
• Hydrogenography
• Thin-film optics
• Thick film