1. Nanometer-resolved chemical analyses of femtosecond laser-induced periodic surface structures on titanium.
- Author
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Kirner, Sabrina V., Wirth, Thomas, Sturm, Heinz, Krüger, Jörg, and Bonse, Jörn
- Subjects
NANOSTRUCTURED materials ,NANOSTRUCTURES ,IRRADIATION ,ENERGY dispersive X-ray spectroscopy ,CHARACTERISTIC X-ray spectrum - Abstract
The chemical characteristics of two different types of laser-induced periodic surface structures (LIPSS), so-called high and low spatial frequency LIPSS (HSFL and LSFL), formed upon irradiation of titanium surfaces by multiple femtosecond laser pulses in air (30 fs, 790 nm, 1 kHz), are analyzed by various optical and electron beam based surface analytical techniques, including micro- Raman spectroscopy, energy dispersive X-ray analysis, X-ray photoelectron spectroscopy, and Auger electron spectroscopy. The latter method was employed in a high-resolution mode being capable of spatially resolving even the smallest HSFL structures featuring spatial periods below 100 nm. In combination with an ion sputtering technique, depths-resolved chemical information of superficial oxidation processes was obtained, revealing characteristic differences between the two different types of LIPSS. Our results indicate that a few tens of nanometer shallow HSFL are formed on top of a ~150 nm thick graded superficial oxide layer without sharp interfaces, consisting of amorphous TiO
2 and partially crystallized Ti2 O3 . The larger LSFL structures with periods close to the irradiation wavelength originate from the laser-interaction with metallic titanium. They are covered by a ~200 nm thick amorphous oxide layer, which consists mainly of TiO2 (at the surface) and other titanium oxide species of lower oxidation states underneath. [ABSTRACT FROM AUTHOR]- Published
- 2017
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