Orientation –free and differentially pumped addition of a low-flux reactive gas beam to a surface analysis system

We describe an example of a piecewise gaschamber that can be customized to incorporate a low flux of gas-phase radicals with an existing surface analysischamber forin situ and stepwise gas-surface interaction experiments without any constraint in orientation. The piecewise nature of this gaschamber provides complete angular freedom and easy alignment and does not require any modification of the existing surface analysischamber. In addition, the entire gas-surface system is readily differentially pumped with the surfacechamber kept under ultra-high-vacuum during the gas-surface measurements. This new design also allows not only straightforward reconstruction to accommodate the orientation of different surfacechambers but also for the addition of other desired features, such as an additional pump to the current configuration. Stepwise interaction between atomic oxygen and a highly ordered pyrolyticgraphite surface was chosen to test the effectiveness of this design, and the site-dependent O-atomchemisorption and clustering on thegraphite surface were resolved by ascanning tunneling microscope in the nm-scale.X-ray photoelectron spectroscopy was used to further confirm the identity of the chemisorbed species on thegraphite surface as oxygen.

Source: Review of Scientific Instruments - November 7, 2016 Category: Physics Authors: Colin Harthcock, Abdolreza Jahanbekam, Jeremy R. Eskelsen and David Y. Lee Source Type: research