Non-thermal regimes of laser annealing of semiconductor nanostructures: crystallization without melting

Authors

I. Mirza, A. V. Bulgakov, Hanna Sopha, Sergey V. Starinskiy, Hana Turčičová, Ondřej Novák, Jiří Mužík, Martin Smrž, Vladimir A. Volodin, Tomáš Mocek, Jan M. Macak, N. M. Bulgakova

Laboratory / Department
Scientific Laser Applications
Citation
Front. Nanotechnol. 2023, 5, 1271832
DOI
10.3389/fnano.2023.1271832
Year
2023

In this work, the conditions of non-thermal ultrafast laser annealing have been analyzed for two kinds of nanostructures: amorphous anodic TiO2 nanotube layers and Ge/Si multilayer stacks. 

For both cases, regimes of crystallization have been found, which yield in preserving the initial nanomaterial morphologies without any melting signs. Ultrafast non-thermal mechanisms of structural material transformation are suggested, which can provide new opportunities for conversion of amorphous semiconductor nanomaterials into a desired crystalline form that is of high demand for existing and emerging technologies.

(a) Schematics of a stress/shock wave initiation upon ultrashort laser annealing of the titania nanotubes. (b) A sketch for phase transformation from the amorphous state to anatase and rutile. (c) SEM image of the TiO2 nanotubes annealed with the picosecond laser pulses.
(a) Schematics of a stress/shock wave initiation upon ultrashort laser annealing of the titania nanotubes. (b) A sketch for phase transformation from the amorphous state to anatase and rutile. (c) SEM image of the TiO2 nanotubes annealed with the picosecond laser pulses.