Single Ion Implantation
At the ion beam center charged particles are typically accelerated to high energies and impact randomly on the surface of materials in order to change their properties. In this particular research topic
we have taken on the challenge of decelerating a handful of ions, in particular highly charged ions, and bringing them in a controlled manner onto surfaces with nanometer precision.
The controlled bombardment of surfaces with highly charged ions holds tremendous potential for coming up with answers to new scientific questions in both basic and applied research. Therefore, the most prominent example is most likely the realization of quantum computers as the placement of individual ions in a well-defined manner is key to their production. In addition, the selective bombardment of existing nanostructures is charting new experimental territory for observing and modifying their physical properties.
At the present state, we designed and commissioned an apparatus called SNIPER (Surface Nanostructures Induced by Potential Energy Release) that produces an ion beam of approx. one millimeter in diameter. Also, the necessary deceleration of the ions to energies as low as a few tens of eV per charge has been achieved. The next step will be the reduction of the beam to single ions and their controlled placement onto the surface. This is intended to be realized by combining an ultrathin glass capillary with the modified tip of an atomic force microscope (see figure below). A prototype of such an AFM tip has already been produced using a focused ion beam machine from within the IBC.
|Schematics of the setup for the single ion implantation through a hole drilled into a cantilever
|Hole drilled into a cantilever by a focused ion beam for the precise implantation of single highly charged ions into a surface (from J. Meijer, T. Vogel, B. Burchard, I.W. Rangelow, L. Bischoff, J. Wrachtrup, M. Domhan, F. Jelezko, W. Schnitzler, S.A. Schulz, K. Singer, and F. Schmidt-Kaler, Appl. Phys. A 83, 321 (2006))