In U.S. Patent Application 20100084634, Toppan Printing Co., Ltd. (Tokyo, JP) and Japan’s National Institute For Materials Science (Tsukuba, JP) disclose a manufacturing method for nano-crystal diamond film. The film can be synthesized on a variety of substrates and contains, as a major component, nano-crystal diamond with a grain diameter from 1 nanometer to less than 1000 nanometers.
This nano-crystal diamond film can be formed on a variety of substrates by means of a plasma chemical vapor deposition method using as a raw material gas containing a hydrocarbon and hydrogen. The apparatus allows the formation of the nano-crystal diamond film to take place outside the plasma region. Substrates may include a silicon substrate, a quartz substrate, a ceramic substrate, a metal substrate, a glass substrate or a polymer substrate.
According to inventors Gamo Hidenori and Toshihiro Ando, the nano-crystal diamond film is applicable to the manufacture of an electrochemical device, an electrochemical electrode, a DNA chip, an organic electroluminescent device, an organic photoelectric receiving device, an organic thin film transistor, a cold electron-emission device, a fuel cell and a catalyst.
Since the nano-crystal diamond film is high in crystallinity, the film is provided with various physical properties which are equivalent to those of normal diamond. Further, since the surface of nano-crystal diamond film is excellent in flatness, the fine working for a semiconductor as well as the formation of a laminated device can be easily applied to the film. The surface of a nano-crystal diamond film is excellent in physical features enabling it to be used for various kinds of applications including enhanced hardness, enhanced Young's modulus, enhanced heat resistance, enhanced heat conductivity, wide band gap, and enhanced resistivity.
The diamond film can be employed for measuring the composition and concentration of a solution. Namely, this diamond film can be applied to an electrochemical device comprising one or more pairs of electrodes (including a detection electrode) to detect the identification and concentration of a substance to be measured by taking advantage of redox reaction of the surface of electrodes.
Since the nano-crystal diamond film in particular is designed to have a very flat surface structure, the technique of refining work for a semiconductor can be easily applied to the nano-crystal diamond film. Namely, the lithography technique using s laser, electron beam, etc. can be applied to the nano-crystal diamond film. As a result, it is possible to realize ultra-fine working of a semiconductor element or the terminal portions thereof, thus making it possible to enhance the sensitivity of the semiconductor element.
The nano-crystal diamond film can be used as the anode or the cathode of the organic electroluminescent device or as a surface layer of anode or a surface layer of a cathode of the organic electroluminescent device, and, at the same time, the surface of these electrodes is terminated with an electron-attractive group or an electron-donating group. By doing so, it is possible to realize both a low work function and high work function ranging from 2.8 eV to 6.5 eV, thus making it possible to realize an organic electroluminescent device exhibiting a high luminescence efficiency.
The nano-crystal diamond film can be applied to a cold electron-releasing device. Cold electron-releasing devices (FED) are regarded as useful in particular as an electron source of a high-performance flat panel display devices of the next generation. This FED can be employed substituting for the thermoelectronic emission device of conventional CRT. Specifically, by making use of the fine working technique for semiconductor, a minute field emission type electron-releasing device (cold electron-releasing device) is attached to every pixel to thereby make it possible to reduce the thickness of display device while taking advantage of the same principle of cathode luminescence as that of CRT which is excellent in high luminescence and in high display speed.