Phase transformation in AFM silicon tips
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2017-06-26 |
| Journal | Nanotechnology |
| Authors | Malgorzata KopycinskaâMĂŒller, Martin Barth, M KĂŒttner, Bernd Köhler |
| Citations | 3 |
Abstract
Section titled âAbstractâWe confirmed the occurrence of phase transformations in an atomic force microscopy silicon tip during loading and unloading experiments performed on a polycrystalline Ti sample. The influence of the phase transformations on the effective mechanical and electrical properties of the tip was observed with the help of load-unload curves measured simultaneously for the tip-sample contact stiffness k <sup></sup> and the effective electrical resistance of the system R <sub>eff</sub>. We used the atomic force acoustic microscopy (AFAM) method to determine the values of k <sup></sup>. To measure the changes in R <sub>eff</sub>, we combined a high voltage source/measure unit with the existing AFAM system. The data obtained showed that the phase transformation from Si-I to Si-II is preceded by other structural changes such as formation of distorted diamond structures and formation of Si-III. This conclusion was reached after observing a small hysteretic behavior in the load-unload stiffness curve accompanied by only very small changes in the resistance of the tip-sample system occurring on the unloading. The coinciding of a sudden increase in the values of the contact stiffness with a decrease in the resistance of the system indicated that the formation of metallic Si-II occurred in the subsequent measurements. The interpretation of our results found confirmation in the results of molecular dynamics and atomistic simulations performed for silicon under nanoindentation experiments.