Growth of high spatial frequency periodic ripple structures on SiC crystal surfaces irradiated with successive femtosecond laser pulses

Go Obara, Hisashi Shimizu, Taira Enami, Eric Mazur, Mitsuhiro Terakawa, Minoru Obara

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

We present experimentally and theoretically the evolution of high spatial frequency periodic ripples (HSFL) fabricated on SiC crystal surfaces by irradiation with femtosecond laser pulses in a vacuum chamber. At early stages the seed defects are mainly induced by laser pulse irradiation, leading to the reduction in the ablation threshold fluence. By observing the evolution of these surface structures under illumination with successive laser pulses, the nanocraters are made by nanoablation at defects in the SiC surface. The Mie scattering by the nanoablated craters grows the periodic ripples. The number of HSFL is enhanced with increasing pulse number. At the edge of the laser spot the Mie scattering process is still dominant, causing the fabrication of HSFL. On the periphery of the spot SiC substrate remains a semiconductor state because the electron density in the SiC induced by laser irradiation is kept low. The HSFL observed is very deep in the SiC surface by irradiating with many laser pulses. These experimental results are well explained by 3D FDTD (three-dimensional finite-difference time-domain) simulation.

Original languageEnglish
Pages (from-to)26323-26334
Number of pages12
JournalOptics Express
Volume21
Issue number22
DOIs
Publication statusPublished - 2013 Nov 4

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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