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Investigation on Microstructural Morphological Changes for Laser Irradiated Targets
Presented By:Tehseen Naz2012/II-M.phil-App-Phy-09
Supervised By:Prof. Dr. Anwar Latif
Department of physics, University of Engineering and Technology, Lahore.
ContentsObjectivesIntroduction ExperimentationCharacterization Results and DiscussionConclusionsApplicationsFuture work
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Objective
To Investigate the evolution of microstructures at the surface of nano second laser irradiated materials (Au, Al, Pt, Cu, Si, ABS).
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Introduction
Laser Matter InteractionInteraction of nanosecond laser pulse with matter causes: Absorption Thermal excitations Melting Microstructure growth Material ablation [1]
Figure 1: Interaction of ns laser pulse with matter.
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[1] Dolgaev, S.I. Kirichenko, N.A. Simakin, A.V. & G.A. Shafeev, “Laser assisted growth of microstructures on spatially confined substrates”, Applied Surface Science, 253, 7987 – 799 (2007).
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The interaction of nano-second laser with target material may produce [2]: Ripples Micro-droplets Cracks Crater Debris
Continued…
[2] D.Bauerle, Laser processing and chemistry 3rd Edition (Spring-Verlag Berlin, 2000) 215-217.
Experimentation
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Experimental Conditions
Targets
4 N pure fine polished Copper, aluminum, platinum, gold, Silicon (P-type) and Acrylonitrile butadiene styrene (ABS)
Nd:YAG Laser (1064nm,10mJ, 9-12ns, 1.1 MW)
IR- Transmission Lens Focal length (f ) = 8cm
Number of laser shots 25, 50, 75, 100, 125, 150Atmosphere Ambient air
Table 1: Experimental conditions for material irradiations.
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Figure 2: Schematic diagram of laser irradiation on targets.
Experimental Setup
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Nd:YAG Laser
Target Holder Stand
Target MaterialFocusing Lens
8cm
Focused Laser Beam
Characterization Technique
Optical Microscope(Olympus STM 6 with minimum read out of 0.1 µm)To explore the surface morphology of the targets.
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Results and Discussion
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Surface Morphology of Copper
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Figure 3: Optical micrographs of Cu irradiated by (a) 25 (b) 50 (c) 75 (d) 100 (e) 125 (f) 150, laser shots.
Area of HAZ
(b)
Crater
Area of HAZ (a)
Crater Area of HAZ
(c)
Crater
Area of HAZ
(d)
Crater
Area of HAZ
(e)
Crater
Area of HAZ
(f)
Crater
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Sr no. No. of laser shots
Area of HAZ(μm2)
Crater depth(10-3) μ m
Crater area(10-12 m2)
Crater volume(10-21 m3)
Ablated mass(10-21
Kg)
1 25 177128.4 14.2 746.1996 10596.03 94940470
2 50 189253.4 26.6 933.8506 24840.43 222570216
3 75 224442.7 57.9 1683.995 97503.3 873629564
4 100 251736.4 67 1734.868 116236.2 1.041E+09
5 125 274585.5 78.9 2618.948 206635 1.851E+09
6 150 298685.9 90 3377.419 303967.7 2.724E+09
Continued…Table 2: HAZ, crater and ablated mass with increasing the number of laser shots.
Surface Morphology of Platinum
14Figure 4: Optical micrographs of Pt irradiated by (a) 25 (b) 50
(c) 75 (d) 100 (e) 125 (f) 150, laser shots.
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Sr no. No. of laser shots
Area of HAZ(μm2)
Crater depth(10-3) μ m
Crater area(10-12 m2)
Crater volume(10-21 m3)
Ablated mass(10-21
Kg)
1 25 4024.35 0.1 13568.38 1356.838 29104172
2 50 8420.511 2.4 17065.22 40956.52 878517342
3 75 8608.529 27 17932.73 484183.6 1.039E+10
4 100 9455.374 29.5 20756.38 612313.2 1.313E+10
5 125 10257.06 34 22735.52 773007.6 1.658E+10
6 150 11955.4 34.2 25850.42 884084.4 1.896E+10
Continued…Table 3: HAZ, crater and ablated mass with increasing the number of laser shots.
Surface Morphology of Aluminum
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Figure 5: Optical micrographs of Al irradiated by (a) 25 (b) 50 (c) 75 (d) 100 (e) 125 (f) 150, laser shots.
Area of HAZ
Area of HAZ
Area of HAZ
Area of HAZ
Area of HAZ
Area of HAZ
Crater
CraterCraterCrater
Crater
(a) (b) (c)
(d) (e) (f)
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Sr no. No. of laser shots
Area of HAZ(μm2)
Crater depth(10-3) μ m
Crater area(10-12 m2)
Crater volume(10-21 m3)
Ablated mass(10-21
Kg)
1 25 30047.232 1063.263 2126.527 5741621.8
2 50 31267.194.8 1338.255 6423.624 17343785
3 75 32162.328.1 3634.566 29439.99 79487965
4 100 36335.529.4 4298.917 40409.82 109106502
5 125 50325.0714 4877.911 68290.75 184385025
6 150 51775.8630 6139.814 184194.4 497324896
Continued…Table 4: HAZ, crater and ablated mass with increasing the number of laser shots.
Surface Morphology of Gold
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Figure 6: Optical micrographs of Au irradiated by (a) 25 (b) 50 (c) 75 (d) 100 (e) 125 (f) 150, laser shots.
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Sr no. No. of laser shots
Area of HAZ(μm2)
Crater depth(10-3) μ m
Crater area(10-12 m2)
Crater volume(10-21 m3)
Ablated mass(10-21
Kg)
1 25 76574.96 22 0 0 0
2 50 169849.3 23 3649.418 83936.61 1.62E+09
3 75 178786.8 23.7 3895.001 92311.52 1.782E+09
4 100 182392 24.8 3983.038 98779.35 1.906E+09
5 125 190010.2 26.8 7839.187 210090.2 4.055E+09
6 150 191134.2 27 16619.69 448731.7 8.661E+09
Continued…Table 5: HAZ, crater and ablated mass with increasing the number of laser shots.
Surface Morphology of Silicon
20Figure 7: Optical micrographs of Si irradiated by (a) 25 (b) 50
(c) 75 (d) 100 (e) 125 (f) 150, laser shots.
CraterReflectio
n patterns
(f)
Crater
Reflection
patterns
(e)
CraterCrater
Reflection patternsReflection
patterns
Crater
Reflection patterns
(d)
Crater
(a) (b) (c)
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Sr no. No. of laser shots
Area of HAZ(μm2)
Crater depth(10-3) μ m
Crater area(10-12 m2)
Crater volume(10-21 m3)
Ablated mass(10-21
Kg)
1 25 8420.511 6.7 10556.55 70728.89 164091019
2 50 15486.46 8 12264.06 98112.44 227620862
3 75 22826.04 18.4 12429.49 228702.7 530590182
4 100 30850.07 45 14377 646964.9 1.501E+09
5 125 34919.18 46 16472.49 757734.7 1.758E+09
6 150 44382.7 76 16981.73 1290612 2.994E+09
Continued…Table 6: HAZ, crater and ablated mass with increasing the number of laser shots.
Surface Morphology of Acrylonitrile Butadiene Styrene (ABS) Polymer
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Figure 8: Optical micrographs of ABS irradiated by (a) 25 (b) 50 (c) 75 (d) 100 (e) 125 (f) 150, laser shots.
(a)
(d)
(b) (c)
(e) (f)Crater
Crater
Area of HAZ
Area of HAZ
Area of HAZ
Area of HAZ
Area of HAZ
Area of HAZ
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Sr no. No. of laser shots
Area of HAZ(μm2)
Crater depth(10-3) μ m
Crater area(10-12 m2)
Crater volume(10-21 m3)
Ablated mass(10-21
Kg)
1 25 415.265 100 139.5522 13955.22 15071641
2 50 551.2663 220 10661.74 2345584 2.533E+09
3 75 5024 380 12266.78 4661377 5.034E+09
4 100 5182.227 530 14166.79 7508399 8.109E+09
5 125 5246.204 620 16809 10421579 1.126E+10
6 150 6148.316 630 23775 14978250 1.618E+10
Continued…Table 7: HAZ, crater and ablated mass with increasing the number of laser shots.
Graphical analysis
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Comparison of HAZ of irradiated materials (Al, Au, Pt, Cu, Si, ABS)
25 Figure 9:A plot between area of HAZ and number of laser shots.
Comparative graph between crater depth and number of laser shots
26 Figure 10:A plot between crater depth and number of laser shots.
Comparative graph between crater area and number of laser shots
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Figure 11:A plot between crater area and number of laser shots.
Comparative graph between crater volume and number of laser shots
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Figure 12:A plot between crater volume and number of laser shots.
Comparative graph between ablated mass and number of laser shots
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Figure 13:A plot between ablated mass and number of laser shots.
Conclusions
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Microstructures (ripples, crater and micro droplets) are formed on irradiated surfaces.
All targets (Au, Al, Pt, Cu, Si, ABS) show a small crater formation but Au shows ripples with crater.
Area of HAZ, crater depth, crater area, crater volume and ablated mass increases by increasing number of laser shots.
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Sr.No.
Material Name
Trends
No. of laser
shots Vs area of
HAZ
No. of laser
shots Vs Crater depth
No. of laser shots Vs Crater
area
No. of laser
shots Vs Crater volume
No. of laser shots Vs Crater ablated mass
1 Au Exponential
Exponential
Exponential
Exponential
Boltzmann
2 Pt Exponential
Boltzmann
Polynomial Exponential
Exponential
3 Al Boltzmann Exponential
Exponential
Exponential
Exponential
4 Cu Linear Boltzmann
Exponential
Polynomial Boltzmann
5 Si Linear Exponential
Boltzmann Exponential
Exponential
6 ABS Boltzmann Polynomial
Exponential
Exponential
Exponential
Applications: Surface microstructuring is addressing significant
areas of research like• Ripple transmission grating [3]• Data storage devices• Corrosion protection [4]
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[3] H.Y. Zheng, T.T. Tan, W. Zhou, “Studies of KrF laser-induced long periodic structures on polyimide”, Optics and Lasers in Engineering, 47, 180–185 (2009).[4] L. Honga, Ruslia, X.C. Wangb, H.Y. Zhengb, H. Wanga, H.Y. Yuc, “Femtosecond laser fabrication of large-area periodic surface ripple structure on Si substrate”, Applied Surface Science , 297 , 134–138 (2014).
Future WorkComparison of electrical, optical, surface and morphological properties under the same conditions on different class of materials can be performed and the correlation may be formed between irradiated and un-irradiated materials by varying different parameters.
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Thank you !
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