This article outlines the effectiveness of the plasma treatment capability of the Henniker Plasma cleaner at different power levels and times.
Plasma Cleaning Method
A Henniker HPT-100 Plasma Cleaner with a Jeol TEM sample holder adapter was employed to study its effectiveness, with dual digital MFC gas mixing and continuously variable power output ranging from 0-100 W.
Samples were input into the equipment using the front feedthrough adapter and were subsequently cleaned with an Ar:O2 95:5 mixture at low power (20 W and 50 W) in increments of 30 seconds. The results for the accumulated treatment time are discussed below.
Figure 1. Henniker Plasma with TEM Adapter. Image Credit: Henniker Plasma
Preparation and Examination Methods
The following methods were used for preparation and examination:
A holey carbon-coated Cu TEM grid.
JEM 2800 (Scanning) Transmission Electron Microscope was employed to study the samples using a voltage of 200 kV and C2 aperture of 70 and 40 um.
Bright-field imaging mode with CCD High magnification lattice resolution imaging mode utilizing CCD.
Figure 2 & 3. Analysis Region 50 μm & 2 μm. Image Credit: Henniker Plasma
Cleaning progression for selected thinned analysis region shows gradual carbon loss from the region followed by gradual loss from thicker wall regions.
Image Credit: Henniker Plasma
Conclusion
This study demonstrates the effectiveness of the plasma treatment capability of the Henniker Plasma cleaner at various power levels and times.
The images obtained from the same location with a finder holey carbon grid exhibited a gradual loss of carbon from a small, thinned area of carbon. Initially, the thinned carbon was eliminated (or eaten away). The thick walls were subsequently seen to lose carbon from the edges.
In conclusion, the Henniker HPT plasma cleaner was observed to be suitable for TEM preparation purposes because it offers amazing control over how much carbon is removed from samples. It is suitable for catalyst samples on carbon for hydrocarbon contamination cleaning in the TEM.
Dr. Dogan Ozkaya, Johnson Matthey Technology Centre
Acknowledgments
Produced from materials originally authored by Henniker Scientific Ltd. The original authors wish to acknowledge the work of Dr. Dogan Ozkaya and the microscopy group members of Johnson Matthey Technology Centre.
This information has been sourced, reviewed and adapted from materials provided by Henniker Plasma.
For more information on this source, please visit Henniker Plasma.