Modification of Optical Properties of Surface Layers and Thin Films by Laser Treatment

Authors L.V. Poperenko, V.V. Stukalenko, I.V. Yurgelevych

Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska St., 01601 Kyiv, Ukraine

Issue Volume 11, Year 2019, Number 3
Dates Received 10 April 2019; revised manuscript received 10 June 2019; published online 25 June 2019
Citation L.V. Poperenko, V.V. Stukalenko, I.V. Yurgelevych, J. Nano- Electron. Phys. 11 No 3, 03032 (2019)
PACS Number(s) 78.68. + m, 81.40.Tv
Keywords Nanostructured silicon, Rapidly quenched alloys, Laser treatment, Ellipsometry (5) , Optical anisotropy.

Optical conductivity of silicon wafer modified by femtosecond laser irradiation as well as an effect of laser treatment on the optical properties of surface layers of rapidly quenched multicomponent alloy ribbons have been investigated by ellipsometry. The samples of the nanostructured silicon as isolated cells were formed on the single crystal silicon wafers by method of laser ablation. Laser beam scanning modes provide in air atmosphere the synthesis of nanostructured silicon dioxide particles as well as silicon nanoparticles. It was established that ellipsometric parameters and optical conductivity ( of the cells of the nanostructured silicon are significantlly changes for two cell orientations relatively p-direction of the sample. This means that the formed silicon nanostructures possess essential optical anisotropy as a result of a deformation influence of laser ablation and an appearance of elastic stresses within the surface layer of the nanostructured silicon. The optical anisotropy was not found for silicon areas which were not subjected to laser action and located between the cells of the nanostructured silicon.The obtained variations of the optical conductivity ( of rapidly quenched multicomponent alloy ribbons as functions of laser pulse energy E as well as a number of pulses N are nonmonotonic and reach a minimum at certain E and N values. Such behavior of their ( during the first phase of laser treatment is related to the so-called “laser-induced vitrification” effect owing to additional atomic disordering of the surface layers of ribbons which are not completely amorphous in the initial state but contain some amount of a crystalline phase. Then during the second phase of such treatment the current amorphous structure was continued to be formed and relaxed within surface layer. At the third phase of laser heat action the annealing of the surface ribbon was observed due to reaching some sufficient laser radiation dose which leads to the formation of the crystalline phase and, therefore, to an increase in (.