Nanostructured surfaces
 
Heating and coagulation of nanoparticles in a plasma jet Kravchenko O.Yu., Maruschak I.S.
The Chair of Physical Electronics, Faculty of Radiophysics, Electronics and Computer Systems, Taras Shevchenko National University of Kyiv. Volodymirs’ka Str., 64, Kyiv-01601, Ukraine. 
E-mail: kay@univ.kiev.ua

The growth of thin and ultra-thin films may be achieved using a large variety of techniques such as chemical vapour deposition, RF sputtering, pulsed laser deposition or plasma enhanced chemical vapour deposition [1,2]. Film morphology and structure can greatly enhance the physical properties of thin films. One of the most promising methods for creating nanostructured films is the use of plasma jets of low pressure with nanoparticles [3]. In this case, it is important to control the size of the nanoparticles, their temperature and energy to optimize the properties of the films.
In this paper, the heating and coagulation of dust nanoparticles in a plasma jet that expands into rarefied gas are studied using computer simulations. In our model, we use a hydrodynamic model for describing the dynamics of a plasma with a multidisperse phase, as well as a sectional method for describing the coagulation of nanoparticles. The equations take into account the heating of nanoparticles due to their collisions with electrons, ions, and neutral atoms.
It is shown that nanoparticles are strongly heated in the plasma at plasma pressures at the inlet p=1-100 Torr, and the temperature of the dust particles depends on their radius and plasma density. In the case of a rarefied plasma, small particles acquire a higher temperature, and in the case of a denser plasma the temperature of larger particles is higher. The latter effect is associated with the significant role of energy exchange of dust particles with neutral atoms in the case of a denser plasma and small particles.

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