Further Applications of Diamond Films

Numerous other fields of diamond film application are known, and more are sure to emerge in the future. One potential application makes use of the diamond films high thermal conductivity, which by far exceeds that of any other bulk material. Hence, diamond is suitable for heat dissipation, for example, in electronic circuitry. For instance, a surface may be coated with a layer of CVD diamond which then effects the removal of heat Another conceivable setup would be using a 

Diamond films may be polycrystalline or monocrystalline layers. In polycrystalline films, the diameter of particles is either on the range of micrometers, or they measure just a few nanometers across (UNCD). The preparation is mostly achieved by deposition from the gas phase (CVD methods). A variety of gaseous hydrocarbons like methane serve as carbon source. Film formation only occurs in the presence of atomic hydrogen that must be generated in situ, for example, in a plasma, on a hot filament, or in a flame. The deposition takes place on a substrate heated at 800-1200 °C. 

Diamond films exhibit different characteristics depending on their morphology and mode of preparation. They feature great hardness and a low frictional coefficient. Doping can turn the wide gap semiconductor (bandgap -5.5 eV) into a semiconductor or even into a material with a conductivity comparable to that of metals (e.g., upon boron doping). 

The electrochemical properties of diamond films are very promising. Films doped for better conductivity feature a wide potential window, and owing to their stability and fast response times, etc., they suit very well to a use as electrode material in electroanalysis. Diamond films with their surface being suitably modified further suggest themselves for the analysis of biological material. Due to a low unspecific adsorption, interactions will occur only at those positions carrying the respective structure. This is of considerable interest for the development of the so-called lab on a chip. 

Further applications of diamond films lie in a mechanically resistant coating of components and implants. Moreover, the use in electronic devices seems near at hand now, and one may well assume that diamond films will at least partially replace silicon in this field. The optical quahties of diamond render free-standing films an ideal material for windows in spectroscopic apparatus, etc. Rehable methods of preparation and a controllable doping have been estabhshed, which altogether allow for a large scale, commercial apphcation of diamond films. 

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