High-density regular arrays of nanometer-scale rods formed on silicon surfaces via femtosecond laser irradiation in water.
We report on the formation of high-density regular arrays of nanometer-scale rods using femtosecond laser irradiation of a silicon surface immersed in water. The resulting surface exhibits both micrometer-scale and nanometer-scale structures. The micrometer-scale structure consists of spikes of 5-10 mum width, which are entirely covered by nanometer-scale rods that are roughly 50 nm wide and normal to the surface of the micrometer-scale spikes. The formation of the nanometer-scale rods involves several processes: refraction of laser light in highly excited silicon, interference of scattered and refracted light, rapid cooling in water, roughness-enhanced optical absorptance, and capillary instabilities.
Department of Physics and School of Engineering and Applied Sciences, Harvard University, 9 Oxford Street, Cambridge, Massachusetts 02138, USA.
Mengyan
M
Shen
James E
JE
Carey
Catherine H
CH
Crouch
Maria
M
Kandyla
Howard A
HA
Stone
Eric
E
Mazur