Periodic nanostructures on Si(100) surfaces generated by high-repetition rate sub-15 fs pulsed near-infrared laser light

Abstract

Nanoscale rifts and ripples at a periodicity of 130 nm were generated on Si(100) surfaces immersed in water using tightly focused 800 nm 12 fs pulsed 85 MHz laser light at subnanojoule pulse energies. At radiant exposure close to the ablation threshold rifts were typically 20-50 nm in width and 70 nm in depth running perpendicular to the laser polarization. On increase of the irradiance, the rifts broadened and formed periodic ripples, whereas at highest exposure, a random nanoporous surface topology emerged. Rift and ripple formation is explained by laser-induced standing surface plasma waves, which result in periodic variation of dissipation and ablation.

Study on morphology of high-aspect-ratio grooves fabricated by using femtosecond laser irradiation and wet etching

“…Nano-ripples formed on materials surface or inside materials have been reported widely [25][26][27][28]. Until now, only surface nano-ripples were observed on silicon [29][30][31]. The interference of incident light and surface plasma wave has been widely adopted to clarify the formation of the surface nano-ripples on silicon [29][30][31].…”

“…Until now, only surface nano-ripples were observed on silicon [29][30][31]. The interference of incident light and surface plasma wave has been widely adopted to clarify the formation of the surface nano-ripples on silicon [29][30][31]. However, there has been few report concerning nano-ripples on sidewalls of holes or grooves induced by femtosecond laser irradiation.…”

Raman spectroscopy and periodic surface structures of Mg:ZnO thin film fabricated by femtosecond laser pulses

“…A great many research works have been done in this field in past several decades [2][3][4][5][6][7][8][9][10][11][12] . For instances, nanogratings were produced by radial and azimuthal laser polarization modes [13] , pyramid-like spikes in a single crystal superalloy upon irradiation with picosecond laser pulses were investigated [14] .…”

Si nanostructures based solar cells

“…However, in most of previous work, the nano-ripple structures were only formed in small area of approximately the laser spot size such as in the annular region of the laser irradiated area of the substrate [182,183]. Also, the modulation depth of the produced nano-ripples is still shallow and only in the order of 100 nm [177,179,184]. In this section, we report the FS laser induced fabrication of a well-controlled large area periodic nano-ripple structure on a Si substrate.…”

“…The induced LIPSS structure can be attributed to the interference between the incident and scattered laser light [170], nonlinear energy absorption and nonequilibrium thermodynamics process [150][151][152], local field enhancement [171,172] or surface plasmons modes [172][173][174]. While early research on the LIPSS structure is focused on using nanosecond laser [175], currently, picosecond or femtosecond (FS) laser has gained more attention due to better heat confinement and structural dimension control [176][177][178][179].…”