Correlated topographic and structural modification on Si surface during multi-shot femtosecond laser exposures: Si nanopolymorphs as potential local structural nanomarkers

• DOI: 10.1016/j.apsusc.2017.04.215
• Publication Date: 2017-04-27T04:17:37Z
• Authors: A.A. Ionin; S.I. Kudryashov; A.O. Levchenko; L.V. Nguyen; I.N. Saraeva; A.A. Rudenko; E.I. Ageev; D.V. Potorochin; V.P. Veiko; E.V. Borisov; D.V. Pankin; D.A. Kirilenko; P.N. Brunkov
• Keywords: Hydrostatic pressure; Nanocrystalline material

Abstract High-pressure Si-XII and Si-III nanocrystalline polymorphs, as well as amorphous Si phase, appear consequently during multi-shot femtosecond-laser exposure of crystalline Si wafer surface above its spallation threshold along with permanently developing quasi-regular surface texture (ripples, microcones), residual hydrostatic stresses and subsurface damage, which are characterized by scanning and transmission electron microscopy, as well as by Raman micro-spectroscopy. The consequent yields of these structural Si phases indicate not only their spatially different appearance, but also potentially enable to track nanoscale, transient laser-induced high-pressure, high-temperature physical processes – local variation of ablation mechanism and rate, pressurization/pressure release, melting/resolidification, amorphization, annealing – versus cumulative laser exposure and the related development of the surface topography.