Chemical Processes of Ions
Formation - Transport - Reactivity
Reactive ion surface
scattering
In the project concerning ion-molecule reactions we mentioned the relevance of IMR for e.g. reactive ion etching (RIE). In this project we specifically investigate the interaction of ions with surfaces.
This interaction can be divided in several regimes. For interaction energies (impact energies) > 50 eV in general modification of the surface dominates (etching, implantation, etc.). For interaction energies < 50 eV the analysis fo the surface dominates (soft landing, neutralization, reactive scattering, etc.).
One goal of our work is to find selectivities in the reactive scattering of ions from different kinds of surfaces. Particular emphasis is on selectivities which might be induced by specific quantum states of molecular ions. This is one application of ions formed in project no. 1. Surfaces which are of particular interest include semiconductors (Si) and doped semiconductors (GaAs).
We are also investigating surfaces covered by molecular films or surfaces covered by a selfassembled monolayer (SAM). Here, the focus of our work is on the hyperthermal region, where the question of surface/film analysis can be investigated, possibly going into the field of molecular or even chiral recognition.
A recent example from our research is the reactive scattering of state selected ammonia ions from ammonia covered ITO surface, where elastic scattering as well as H abstraction and H loss is observed, depending on the impact energy.
References :
T. Kolling, S. Sun, K.-M. Weitzel, Int. J. Mass
Spectrom., 277, 245–250, (2008)
Reactive scattering of NH3+ (v, J) ions at film
covered indium tin oxide (ITO) surfaces.
http://dx.doi.org/10.1016/j.ijms.2008.06.014
