Silicon-based nanocrystals represent a promising resource both for next-generation electronic devices and for nano-photonics applications but require precise size, shape and position control. In this thesis the fabrication of Si- and SiGe-based nanocrystals by templated solid-state dewetting of thin silicon films (SOI) and their use in silicon photonics as dielectric Mie resonators will be studied. Islands and wires formation, organization, positioning and composition will be studied by dark-field, atomic force and scanning electron microscopy. The capabilities of this top-down/bottom-up hybrid method in engineering the SOI dewetting fronts thus organizing the nanocrystals in assemblies much more complex than the original etched pattern will be studied. By a combination of electron beam lithography and reactive ion etching the optimised conditions the shape of the islands, their number and their relative position will be controlled with a precision of better than 10%. Furthermore, the effects of germanium alloying leading to a collapse in the number of nucleated islands and to the onset of puzzling bimodal size distributions of ordered nanocrystals will be also considered.
 
Video : https://www.youtube.com/watch?v=Eyq7iyMitCQ
 
This activity will be carried out in LNESS laboratory, Como
monica.bollani@polimi.it, monica.bollani@ifn.cnr.it
Responsabile : Dr. Monica Bollani, http://lness.como.polimi.it/monicabollani.php
ufficio: 031 3327356 , laboratorio LNESS, via Anzani 42 , Como