scholarly journals Comparison of sub-micro/nano structure formation on polished silicon surface irradiated by nanosecond laser beam in ambient air and distilled water

2013 ◽  
Vol 31 (3) ◽  
pp. 465-473 ◽  
Author(s):  
Maliheh Sobhani ◽  
Mohammad Hossein Mahdieh
Keyword(s):  
Structure Formation ◽  
Silicon Surface ◽  
Laser Pulses ◽  
Ambient Air ◽  
Nanosecond Laser ◽  
Distilled Water ◽  
Nano Structure ◽  
Optical Reflectivity ◽  
Surface Cluster ◽  
Cluster Density

AbstractThis paper compares sub-micro/nano structure formation on polished silicon surface irradiated by nanosecond laser pulses in ambient air and distilled water. Surface cluster density and optical reflectivity of silicon surface (at a typical wavelength of λ = 632 nm) were studied in terms of number of laser pulses and laser fluence. The surface density and optical reflectivity give information on clusters filling factor and clusters height respectively. The results show that the values of surface cluster density and clusters height strongly depend on laser pulse numbers and interacting ambient. Comparing to air, distilled water as an interacting ambient can affect more significantly the clusters height.

scholarly journals Femtosecond laser ablation of brass: A study of surface morphology and ablation rate

2012 ◽  
Vol 30 (3) ◽  
pp. 473-479 ◽  
Author(s):  
Mohamed E. Shaheen ◽  
Brian J. Fryer
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Surface Morphology ◽  
Fine Particles ◽  
Femtosecond Laser Ablation ◽  
Laser Pulses ◽  
Ambient Air ◽  
Ablation Rate ◽  
Femtosecond Laser Pulses ◽  
Nanosecond Laser

AbstractThe interaction of near infrared femtosecond laser pulses with a Cu based alloy (brass) in ambient air at atmospheric pressure and under different laser conditions was investigated. The effects of laser fluence and number of pulses on surface morphology and ablation rate were studied using scanning electron microscopy (SEM) and optical microscopy. Ablation rates were found to rapidly increase from 83 to 604 nm/pulse in the fluence range 1.14–12.21 J/cm2. At fluence >12.21 J/cm2, ablation rates increased slowly to a maximum (607 nm/pulse at 19.14 J/cm2), and then decreased at fluence higher than 20.47 J/cm2 to 564 nm/pulse at 24.89 J/cm2. Large amounts of ablated material in a form of agglomerated fine particles were observed around the ablation craters as the number of laser pulses and fluence increased. The study of surface morphology shows reduced thermal effects with femtosecond laser ablation in comparison to nanosecond laser ablation at low fluence.

Formation of Periodical Sub-Micron Sized Structures on Silicon by Interfered Nanosecond Laser Pulses

2010 ◽  
Vol 97-101 ◽  
pp. 3803-3806
Author(s):  
Yong Xiang Hu ◽  
Heng Zhang ◽  
Zheng Qiang Yao
Keyword(s):  
Cost Effective ◽  
Laser Pulses ◽  
Laser Beams ◽  
Nanosecond Laser ◽  
Effective Technique ◽  
First Order ◽  
Direct Fabrication ◽  
Cost Effective Technique ◽  
Nanosecond Laser Pulses ◽  
Micro Structuring

Laser interference micro-structuring is a relatively efficient and cost-effective technique for fabricating periodical micro-nano-structuring surfaces. The direct fabrication of sub-micron sized dot array on silicon was performed by four interfering nanosecond laser beams with a diffractive beam splitter. The mechanism to form the dot array was analyzed and it was found that the obtained conical dot array had a negative shape of the interference pattern of four laser beams. A second-order peak between two first-order peaks also occurred due to the liquid-solid expansion.

Fabrication and Characterization of Si Nano-Columns by Femtosecond Laser

2012 ◽  
Vol 16 ◽  
pp. 15-20 ◽  
Author(s):  
Omid Tayefeh Ghalehbeygi ◽  
Vural Kara ◽  
Levent Trabzon ◽  
Selcuk Akturk ◽  
Huseyin Kizil
Keyword(s):  
Laser Ablation ◽  
Femtosecond Laser ◽  
Laser Beam ◽  
Chemical Etching ◽  
Silicon Surface ◽  
Laser Pulses ◽  
Laser Beam Profile ◽  
Fs Laser ◽  
Fabrication And Characterization

We fabricated Si Nano-columns by a femtosecond laser with various wavelengths and process parameters, whilst the specimen was submerged in water. The experiments were carried out by three types of wavelengths i.e. 1030 nm, 515nm, 343nm, with 500 fs laser pulses. The scales of these spikes are much smaller than micro spikes that are constructed by laser irradiation of silicon surface in vacuum or gases like SF6, Cl2. The Si nano-columns of 300 nm or less in width were characterized by SEM measurements. The formation of these Si Nano-columns that were revealed by SEM observation, indicates chemical etching with laser ablation occurred when surface exposed by laser beam. We observed 200 nm spikes height at the center of laser beam profile and the ones uniform in height at lateral incident area.

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