Plasma Processing Group

NIMS

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Plasma Processing Group is aiming to synthesize functional materials by controlling the chemical reaction fields through plasma technology. Based on the development of plasma generation methods, we are working on the functionalization of nano-structured ceramic materials, such as the plasma synthesis of nano-scale particles of titanium oxide and diamond, the synthesis of oxide thin films by a pulse-modulated sputtering method, and the fabrication of functional composite materials composed of highly dispersed nano-size particles.

 

Group Leader
Dr. Takamasa ISHIGAKI
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Synthesis of functional nano-size powders in RF thermal plasma

 

Nano-scale particles below 50 nm in size can be easily synthesized through thermal plasma processing. Nanoparticles of titanium oxide, which have been used for the photocatalyst, have also the potential for the application as photonic materials by making nano-scale composites and controlling particle size and crystal phase precisely.

TEM image

photo-luminescence in Eu doped TiO2

Ordering of oxygen vacancies is shown as the contrast in the TEM image of highly Fe doped TiO2 nanoaparticles.

 

A sharp photo-luminescence at the wave length, 617 nm and its excitation spectra in Eu doped TiO2 nanoparticles.

 

 

Materials processing using pulse-modulated RF induction plasma.

 

In the newly developed pulse-modulated RF induction plasma, the time-domain control can be utilized by switching the power level in the order of milliseconds. In the unique plasma process, high concentration of chemically reactive species are formed. Recently, we demonstrated the increase of UV fluorescent efficiency in zinc oxide by hydrogen doping.

Generation of pulse-modulated induction thermal plasma

The electron density after the pulse-on

Generation of pulse-modulated induction thermal plasma, in which high and low power levels are repeated in the order of milisecinds.

 

After the instance of pulse-on the electron density increases very rapidly and high degree of non-equilibrium condition is introduced.