Direct Femtosecond Laser Fabrication of Chemically Functionalized Ultra-Black Textures on Silicon for Sensing Applications

Here, we present the single-step laser-assisted fabrication of anti-reflective hierarchical surface textures on silicon locally functionalized with a photoluminescent (PL) molecular nanolayer. Using femtosecond-laser ablation of commercial crystalline Si wafers placed under a layer of a solution containing rhodamine 6G (R6G) a triethoxysilyl derivative, we fabricated ordered arrays of microconical protrusions with self-organized nanoscale surface morphology. At the same time, the laser-induced temperature increase facilitated surface activation and local binding of the R6G derivative to the as-fabricated nanotextured surface. The produced dual-scale surface textures showed remarkable broadband (visible to near-IR) light-absorbing properties with an averaged reflectivity of around 1%, and the capping molecular nanolayer demonstrated a strongly enhanced PL yield. By performing a pH sensing test using the produced nanotextured substrate, we confirmed the retention of sensory properties of the molecules attached to the surface and validated the potential applicability of the high-performing liquid-assisted laser processing as a key technology for the development of innovative multifunctional sensing devices in which the textured substrate (e.g., ultra-black semiconductor) plays a dual role as a support and PL signal amplifier.

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The role of asymmetric excitation in self-organized nanostructure formation upon femtosecond laser ablation

Applied Physics A ◽

10.1007/s00339-011-6472-3 ◽

2011 ◽

Vol 104 (3) ◽

pp. 969-973 ◽

Cited By ~ 55

Author(s):

Juergen Reif ◽

Olga Varlamova ◽

Sergej Varlamov ◽

Michael Bestehorn

Keyword(s):

Laser Ablation ◽

Femtosecond Laser ◽

Femtosecond Laser Ablation ◽

Nanostructure Formation ◽

Self Organized

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Synthesis of Nanotips Through Femtosecond Laser Ablation of Glass with Assisted Gas

10.32920/ryerson.14656779.v1 ◽

2021 ◽

Author(s):

Nikunj Patel

Keyword(s):

Femtosecond Laser ◽

Building Materials ◽

High Vacuum ◽

Synthesis Method ◽

Femtosecond Laser Ablation ◽

Target Surface ◽

Laser Pulses ◽

Single Step ◽

Femtosecond Laser Irradiation ◽

Ambient Conditions

Nanotips are the key nanostructures for many applications. Until now, the nanotips of only the crystalline materials have been produced via various deposition methods which require sophisticated equipment, high vacuum, and clean room operations. This thesis proposes a single step, rapid synthesis method using femtosecond laser irradiation at megahertz frequency with background flow of nitrogen gas at ambient conditions. Amorphous nanotips are obtained without the use of catalyst. The nanotips grow from highly energetic plasma generated when target is irradiated with laser pulses. The vapor condensates, nanoparticles and droplets from the plasma get deposited back on to the hot target surface where they experience force imbalance due to which the stems for the nanotips growth are initiated. Once the stems are generated, the continuous deposition of vapor condensates [sic] provides building materials to the stems to complete the growth of nanotips. Further study found that the growth of the nanotips is influenced by laser parameters and gas conditions.

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Formation of self-organized regular nanostructures upon femtosecond laser ablation

10.1117/12.596765 ◽

2004 ◽

Cited By ~ 7

Author(s):

Juergen Reif ◽

Florenta A. Costache ◽

Sebastian Eckert ◽

Simona Kouteva-Arguirova ◽

Michael Bestehorn ◽

...

Keyword(s):

Laser Ablation ◽

Femtosecond Laser ◽

Femtosecond Laser Ablation ◽

Self Organized

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The role of asymmetric excitation in self-organized nanostructure formation upon femtosecond laser ablation

10.1063/1.4739897 ◽

2012 ◽

Cited By ~ 6

Author(s):

Juergen Reif ◽

Olga Varlamova ◽

Sergej Varlamov ◽

Michael Bestehorn

Keyword(s):

Laser Ablation ◽

Femtosecond Laser ◽

Femtosecond Laser Ablation ◽

Nanostructure Formation ◽

Self Organized

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Feedback Effect on the Self-Organized Nanostructures Formation on Silicon upon Femtosecond Laser Ablation

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.156-158.535 ◽

2009 ◽

Vol 156-158 ◽

pp. 535-540

Author(s):

Olga Varlamova ◽

Markus Ratzke ◽

Jürgen Reif

Keyword(s):

Laser Ablation ◽

Femtosecond Laser ◽

Femtosecond Laser Ablation ◽

Feedback Effect ◽

Constant Intensity ◽

Pulse Separation ◽

Self Organized ◽

Dose Number ◽

Modified Surface ◽

Accumulated Dose

The role of multi-pulse feedback in self-organized nanostructure (ripples) formation on silicon surface upon femtosecond laser ablation is investigated. For irradiation at constant intensity and pulse repetition rate, the previously postulated feedback effect of accumulated dose with in¬creasing number of pulses is confirmed and investigated in detail: both the modified surface area as well as the complexity and feature size of generated nanostructures increase with accumulated dose. More interestingly, at constant total incident dose (number of pulses times pulse energy) accumu¬lation and feedback depend strongly on temporal pulse separation. The feedback becomes increas¬ingly weaker with increasing time intervals between successive pulses, involving times up to one second and more before individual pulses act independently. In a first attempt to model this long-lived coupling, we find that conduction band electrons, produced by the preceding laser pulse, can provide, indeed, such feedback by facilitating coupling of subsequent pulses for substantial delays. However, the achieved time span of about a millisecond is still significantly shorter than observed experimentally.

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Synthesis of three-dimensional calcium carbonate nanofibrous structure from eggshell using femtosecond laser ablation

10.32920/14640117.v1 ◽

2021 ◽

Author(s):

Amirhossein Tavangar ◽

Bo Tan ◽

Krishnan Venkatakrishnan

Keyword(s):

Calcium Carbonate ◽

Femtosecond Laser ◽

Three Dimensional ◽

Femtosecond Laser Ablation ◽

Bone Substitutes ◽

Cell Interaction ◽

Single Step ◽

Femtosecond Laser Irradiation ◽

Ambient Conditions ◽

Functional Biomaterials

Background Natural biomaterials from bone-like minerals derived from avian eggshells have been considered as promising bone substitutes owing to their biodegradability, abundance, and lower price in comparison with synthetic biomaterials. However, cell adhesion to bulk biomaterials is poor and surface modifications are required to improve biomaterial-cell interaction. Three-dimensional (3D) nanostructures are preferred to act as growth support platforms for bone and stem cells. Although there have been several studies on generating nanoparticles from eggshells, no research has been reported on synthesizing 3D nanofibrous structures. Results In this study, we propose a novel technique to synthesize 3D calcium carbonate interwoven nanofibrous platforms from eggshells using high repetition femtosecond laser irradiation. The eggshell waste is value engineered to calcium carbonate nanofibrous layer in a single step under ambient conditions. Our striking results demonstrate that by controlling the laser pulse repetition, nanostructures with different nanofiber density can be achieved. This approach presents an important step towards synthesizing 3D interwoven nanofibrous platforms from natural biomaterials. Conclusion The synthesized 3D nanofibrous structures can promote biomaterial interfacial properties to improve cell-platform surface interaction and develop new functional biomaterials for a variety of biomedical applications.

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