Chromium Oxide Formation on Nanosecond and Femtosecond Laser Irradiated Thin Chromium Films

TL;DR

This study investigates how nanosecond and femtosecond laser treatments modify the microstructure, morphology, and optical properties of thin chromium coatings, leading to oxide formation and oxygen diffusion.

Contribution

It provides detailed analysis of laser-induced microstructural and morphological changes in chromium coatings, highlighting differences between nanosecond and femtosecond laser effects.

Findings

Laser treatment causes oxide layer formation on chromium films.

Morphological evolution correlates with laser fluence.

Oxygen diffusion increases with laser fluence.

Abstract

Thin coatings of Chromium oxide have been used for applications as absorbing material in solar cells, as protections for magnetic data recording devices and as shields in flexible solar cells. Thin coatings of pure chromium were vacuum deposited on a glass substrate using hot electrons from tungsten filament. These coatings were then treated with a nanosecond and femtosecond laser in ambient conditions. The microstructure, morphology and the color of the coatings treated with laser sources were modified and there was a formation of an oxide layer due to the heat dissipation on the chromium coating from the energetic photons. High-resolution scanning electron microscope studies showed the morphological evolution that are directly correlated with the laser fluence of both the nanosecond and femtosecond lasers. This morphological evolution was accompanied by the microstructural change as observed from the x-ray diffraction patterns, the chromaticity response of the coating was studied by UV-Vis spectrometer and the response of the coating in the visible region evolved with the laser fluences. The Rutherford backscattering depth profiling of the laser treated coatings revealed the diffusion of oxygen atoms in the coating as a result of laser treatment fluence.