Schematic representation of the rf plasma chamber used in this study. A tungsten hot filament is installed between the parallel plate electrodes.
Levitated diamond fine particles in a H2 rf plasma with the hot filament. The conditions are: filament temperature = 2300 K, bottom electrode temperature = 1300 K, top electrode temperature = 1100 K, total pressure= 300 Pa, H2 = 100 sccm, rf input power 50 W.
Sequence of collection of levitated particles with the collector. (a) A p-type Si substrate is used as collector and is installed on a transfer rod. It is in a remote position during the plasma treatment of the particles. (b), (c) It is transferred over the particle levitation region. A bright “spot plasma” appears around the positively dc-biased collector. When it approaches the particles, they are attracted by the spot plasma. (d) The particles attach to the collector if the rf power is decreased from 50 W to 0 W.
The final phase of the particle collection. In each frame, the particle tracks are recorded when the shutter is opened (=11 ms). Those frames are in time sequence (from (a) to (c)). The images are digital processed with negative filter and un-sharp mask filter for easier view. The lateral black line shows the bottom surface of the collector.
SEM image of the surface of the particle collector used in Figs. 3 and 4.
The sequence of the particle collection at RT. By transferring the positively biased collector, the particles are attracted and levitated below the collector. Then the rf input power is gradually reduced from 12 W to 0 W (from (a) to (d)). One can see that the particles do not attach to the collector but fall down when the rf plasma is switched off (d).
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