Ondřej Cibulka visits our group

Ing. Ondřej E. Cibulka, PhD from the Institute of Physics of The Academy of Sciences of the Czech republic is visiting our group between 25th and 30th of November, 2011. Ondřej Cibulka works in the group of Prof. Ivan Pelant, one of the leading workplaces for photoluminescence measurements in the Czech Republic. His work is focused on electrochemical preparation of silicon nanocrystals (nc), modification of their surface and measurement of their optical properties, in particular luminescence. An important motivation for this research is possible application of these nanoparticles for novel sources of optical radiation in the so called silicon nanophotonics. The visit of Ondřej Cibulka is very fruitful and helps us in our aim to prepare crystalline silicon nanoparticles in the non-equilibrium plasma at atmospheric pressure. Future cooperation focused on the characterization and comparison of gas phase plasma-produced and electrochemically etched nanoparticles is planned.

Gast: Lenka Zajickova

Prof. Dr. Lenka Zajíčková from Masaryk University, Brno (Czech  Republic) visited our group between 17th and 21th October. Prof. Zajickova is already for a long time active in the field of plasma deposition of carbon nanotubes and thin films with controlled optical and mechanical properties. She visited our group with support of ERASMUS programme of EU and she participated as a lecturer on the „Thin Films and Nanomaterials“ lecture with four hours programm about plasma technology for preparation of nanomaterials. Moreover, she has given on 19.10.2011 at 16:15 a talk with the title "Correlation between chemical structure and functional properties of plasma-deposited organosilicon and SiO₂ films".

GAST: HSIN-HUNG CHEN

15.08.2011

Hsin-Hung Chen from the National Cheng Kung University in Tainan (Taiwan) is guest for 2 months (July and August 2011) in the research groups "Coupled Plasma-Solid state Systems" and "Reactive Plasmas" and supported during his stay the work within the project C1 of the Research Unit FOR1123. He analyzed with an EMCCD camera and an optical emission spectrometer the transition between alpha and gamma discharge of the coaxial microplasma jet operated in helium with a small oxygen admixture. Additionally, absolute atomic oxygen densities have been determined in both discharge modes by means of molecular beam mass spectrometry to identify the influence of the discharge mode on the plasma chemistry.

Our article selected as highlight in EPJ D!

Article with the title:

Phase resolved optical emission spectroscopy of coaxial microplasma jet operated with He and Ar

written by

J. Benedikt, S. Hofmann, N. Knake, H. Böttner, R. Reuter, A. von Keudell, and V. Schulz-von der Gathen

has been selected as Highlight article in

European Physical Journal D

Phase resolved optical emission spectroscopy is used in this work to study the excitation mechanisms of a coaxial atmospheric-pressure microplasma jet with a hollow capillary as an inner electrode and a ceramic tube with outer metal ring as an outer electrode. This technique allows the determination of changes in the plasma emission within one period of the RF cycle (13.56 MHz). Several operational modes were identified in the jet operating in He: an alpha discharge located in the annular space between the electrodes at low applied voltages, a gamma discharge at the capillary surface at higher voltages, and a hollow cathode like plasma at the capillary tip. By contrast, only one mode of operation was observed in Ar, with a behavior comparable to that of a single microdischarge of a filamentary dielectric barrier discharge.