Application of laser generated moth-eye structure for a periodic terahertz-wave generator

Xi, Yu; Ono, Shingo; Bae, Jongsuck

doi:10.1109/irmmw-thz.2019.8874269

Cited by 2 publications

(1 citation statement)

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“…The emission of terahertz waves from ZnO-based devices is very strong evidence that ZnO also has potential uses for terahertz components [ 8 , 10 ]. In both the UV–visible and terahertz regions, laser processing is an efficient method for realizing thin-film-based devices or nano/microstructure-based functional surfaces [ 11 , 12 , 13 , 14 , 15 ]. ZnO-based thin films fabricated by pulsed laser deposition have been widely reported by a vast number of researchers [ 2 ]; in most of these reports, a UV laser with a nanosecond order pulse duration was used.…”

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confidence: 99%

Femtosecond Laser-Pulse-Induced Surface Cleavage of Zinc Oxide Substrate

Itoigawa

Ono

2021

Micromachines

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The induction of surface cleavage along the crystalline structure of a zinc oxide substrate (plane orientation: 0001) by femtosecond laser pulses (wavelength: 1030 nm) has been reported; a scanning electron microscope image of the one-pulse (pulse energy: 6–60 μJ) irradiated surface shows very clear marks from broken hexagons. This cleavage process differs from the general laser-induced melt process observed on the surfaces of narrower-bandgap semiconductors and other metal materials. This phenomenon is discussed using a multi-photon absorption model, and the pulse-energy dependence of the cleavage depth (less than 3 μm) is quantitatively analyzed. Laser-induced cleavage is found not to occur under multi-pulse irradiation; when more than four pulses are irradiated upon the same spot, the general laser-induced melt process becomes dominant. This cleavage–melt shift is considered to be caused by the enhancement of absorption due to the initial pulses, which is supported by our measurement of cathodoluminescence.

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