RESUMEN
One of the main limitations to the application of clusters on applied areas is the limited production; therefore, it is of great interest to up scale cluster production while keeping good size control. The Matrix-Assembly Cluster Source is a new high flux cluster source, which exploits cluster formation inside a solid rare gas matrix that is sputtered by an ion beam. Clusters are formed and ejected in this process. Here we report the production of Ag clusters when the rare gas is replaced by CO2 for the matrix formation at 20 K. Size distributions were determined from scanning transmission electron microscopy analysis of samples with four different metal loadings, 4%, 8%, 14%, and 23% of Ag atoms to CO2 molecules, and two ion beam energies, 1 keV and 2 keV. Cluster mean size showed weak dependence on metal loading, being ≈80 atoms for the first three concentrations, whereas the change in ion beam energy has caused cluster mean size to shift from 86 to 160 atoms. The results are interpreted in terms of bonding energy between Ag and CO2 and compared to the rare gas (Ar) matrix.
RESUMEN
Understanding the mechanical properties of nanoscale systems requires new experimental and theoretical tools. In particular, force sensors compatible with nanomechanical testing experiments and with sensitivity in the nN range are required. Here, we report the development and testing of a tuning-fork-based force sensor for in situ nanomanipulation experiments inside a scanning electron microscope. The sensor uses a very simple design for the electronics and it allows the direct and quantitative force measurement in the 1-100 nN force range. The sensor response is initially calibrated against a nN range force standard, as, for example, a calibrated Atomic Force Microscopy cantilever; subsequently, applied force values can be directly derived using only the electric signals generated by the tuning fork. Using a homemade nanomanipulator, the quantitative force sensor has been used to analyze the mechanical deformation of multi-walled carbon nanotube bundles, where we analyzed forces in the 5-40 nN range, measured with an error bar of a few nN.