Article
Materials Science, Multidisciplinary
S. Sooraj, Y. R. Yugandhara, N. J. Vasa, A. Kavitha, S. Krishnan, M. Shigeki
Summary: In this study, the micro-scribing process of the Cu film on a dielectric substrate was investigated using lasers with different pulse durations. It was observed that the formation of recast layer near the microchannel occurred when using lasers with pulse durations of 6 ns and 500 ps, while no recast layer was observed when using lasers with pulse durations of 1 ps and 120 fs. XRD analysis revealed the presence of compressive residual stresses in the scribed region with the 6 ns and 500 ps lasers, and tensile residual stresses in the scribed region with the 1 ps and 120 fs lasers. Oxide layer formation was observed in all pulse regimes. A theoretical simulation was conducted to estimate the temperature on the dielectric substrate. Complete removal of Cu from the dielectric substrate would result in thermal damage. A hybrid micro-scribing technique, involving immersion in NaCl solution during the final laser scan, was demonstrated for nanosecond laser processing. Finally, a frequency selective surface (FSS) was fabricated using the hybrid scribing technique.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2022)
Article
Optics
Sooraj Shiby, Nilesh J. Vasa
Summary: This study reports a method for pulsed laser-assisted micro-scribing of Cu from dielectric material, with monitoring using laser-induced breakdown spectroscopy (LIBS). Multiple laser scans were needed for complete Cu removal, and the Cu I line intensity in the LIBS spectra decreased as the microchannel depth increased. Additionally, characteristic emission lines from substrate elements were observed in the LIBS spectra during the final laser scan process.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Materials Science, Ceramics
Chang Liu, Xianze Zhang, Guofeng Wang, Zhifang Wang, Lei Gao
Summary: This paper investigates the ablation evolution behavior of 2.5D Cf/SiC composites, observing the ablation evolution process and recast layer structures at different fiber angles through millisecond laser processing. The study reveals the different stages of ablation evolution experienced by fibers and the diversity of recast layer structures.
CERAMICS INTERNATIONAL
(2021)
Article
Automation & Control Systems
Sheng-gui Chen, Man-qun Lian, Xiao-yu Wu, Jian-guo Lei, Hang Zhao, Tai-jiang Peng, Feng Luo, Jun Yang, Bin Xu
Summary: The study investigated the influence of different electrode materials on the processing characteristics of Ti-6Al-4V alloy. Copper tungsten electrode was found to be the most suitable for machining Ti-6Al-4V alloy, as it exhibited the highest reproduction rate, smallest tool electrode wear, highest material removal rate, and thinnest recast layer thickness.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Avritti Srivastava, Anjali Saini, Jai S. Tawale, Prathap Pathi, Sanjay K. Srivastava
Summary: Nano/micro structuring of silicon via chemical approaches has gained significant research interest due to their excellent light trapping abilities. A comprehensive study on the fabrication of nano/micro-inverted structures using CuCCE of solar grade n-Si wafers and their light trapping ability is presented. The surfaces exhibit a low solar weighted reflection and enhanced Raman signal, and the formation mechanism of such inverted structures is explained. The application of inverted nano/micro light trapping structures in hybrid heterojunction solar cells and other photosensitive devices is also demonstrated.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2023)
Article
Materials Science, Multidisciplinary
Gul Dogan, Frank Chiu, Sam U. H. Chen, Mebil R. T. David, Andreas Michalowski, Michael Schaenzel, Christian Silber, Gisela Schuetz, Corinne Grevent, Kahraman Keskinbora
Summary: Atomic layer deposited (ALD) oxide thin films are attractive for copper encapsulation, passivation, and protection due to their chemical inertness and high-temperature stability. Plasma etching successfully removes the encapsulation layer, providing a clean interface for conductive vias. The study results are essential for future ALD layer applications in the encapsulation of copper and other critical components in semiconductor fabrication processes.
MATERIALS & DESIGN
(2021)
Article
Engineering, Manufacturing
Chang Liu, Cheng Li, Lei Gao, Renfeng Shen
Summary: This study proposes a two-dimensional transient numerical model for micro-hole drilling of 2.5D C/SiC composites with a picosecond laser. The model accurately depicts the evolution of hole shape, including entrance, exit diameter, hole taper, and hole profile dynamics. The study also identifies thermal damage as the main cause of hole quality variation.
JOURNAL OF MANUFACTURING PROCESSES
(2022)
Article
Chemistry, Multidisciplinary
Yiyun Zhu, Zhuoya Ni, Jie Gao, Da Zhang, Shumeng Wang, Jiang Zhao
Summary: The surge in demand for personalized electronic products has led to the development of flexible electronic technology and flexible energy storage devices. This study utilizes a laser scribing technique to pattern MXene and graphene oxide composite films, resulting in shape-controllable MXene and laser scribed graphene patterned electrodes on a flexible substrate. These adaptable devices show exceptional electrochemical performance and the use of laser scribing has important implications for scalable production and modular integration.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2023)
Article
Polymer Science
Yong-il Ko, Min-Jae Kim, Dong-Yun Lee, Jungtae Nam, A-Rang Jang, Jeong-O Lee, Keun-Soo Kim
Summary: In this study, highly sensitive carbon nanomaterials were synthesized using a local laser scribing method, providing a simple and cost-effective approach to create these materials.
Article
Automation & Control Systems
Zan Li, Jianyu Jia, Yanqing Wang, Ming Lv, Shengqiang Yang
Summary: This paper proposes an online polishing method using fluid magnetic abrasives to improve the micro-shaft surface quality. A polishing device is designed and integrated into a micro-EDM machine tool. Experimental results show that the proposed method can effectively improve the surface quality of micro-shafts and remove recast layers.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2023)
Article
Optics
Shifei Han, Haijuan Yu, Chaojian He, Shusen Zhao, Chaoyu Ning, Lu Jiang, Xunchun Lin
Summary: This study demonstrates the successful fabrication of silicon carbide wafers using laser cutting technology, which overcomes the issues encountered in diamond wire cutting. By optimizing the processing parameters, the fabricated wafers have a small cutting width and surface roughness, with no residual stress. This technology has important applications in slicing hard and brittle materials and thinning the backsides of semiconductor devices.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Engineering, Manufacturing
T. Roy, A. Sharma, P. Ranjan, R. Balasubramaniam
Summary: This study numerically calculated the mechanical properties of parent material, heat affected zone (HAZ), and recast layer on micro features fabricated by reverse micro EDM (RMEDM), using nano indentation experiment and finite element analysis (FEA) simulation. Results showed good agreement between numerical and experimental data, with a maximum 11% error in hardness values. The model can predict mechanical properties of surfaces fabricated by micro EDM process, thereby reducing the number of experiments and saving time and cost.
JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME
(2021)
Article
Chemistry, Physical
Yong-il Ko, Geonhee Lee, Min Jae Kim, Dong Yun Lee, Jungtae Nam, A-Rang Jang, Jeong-O Lee, Keun Soo Kim
Summary: This study synthesized carbon nanomaterials using local laser-scribing on a substrate coated with a Cu-embedded polyimide (PI) thin film to reduce processing time and cost. The laser absorption of the Cu-embedded PI thin film was improved, leading to a three-dimensional structure of the carbon nanomaterial that facilitates gas molecule absorption. When exposed to NO2 and NH3, the electrical resistance of the synthesized carbon nanomaterial changed by -0.79% and +0.33%, respectively.
Article
Engineering, Manufacturing
Mengyuan Ren, Fei Lin, Fanghui Jia, Haibo Xie, Ming Yang, Zhengyi Jiang
Summary: The study proposes the use of ultra-thin metal foil rolling for the fabrication of micro composite channels, which improves product function and reduces operational cost. Copper/SS304L composite foils with different rolling reductions and velocities were used to form micro channels, and the characteristics and deformation behaviors of the rolling process were investigated. The results show that the ridges and channels are asymmetrical in all samples, and the surface features, such as scratches and adhesion, become more significant with increased rolling reduction but can be reduced with higher rolling velocity.
JOURNAL OF MANUFACTURING PROCESSES
(2023)
Article
Materials Science, Multidisciplinary
Masaki Omiya, Ayumi Nakajima, Jiwang Yan
Summary: This study found that deep microgrooves improved adhesion strength due to the anchor effect, but there was a limitation in enhancing adhesion strength based on the aspect ratio of the microgroove. LIPSS formation on the mountaintop of the microgroove was effective, while LIPSS on the valley of the microgroove was ineffective.
MATERIALS & DESIGN
(2022)
Article
Engineering, Marine
Della Thomas, S. Surendran, Nilesh J. Vasa
Summary: This study focuses on the issue of ship hull fouling in tropical ocean environment, analyzing voyage data taking into account wind and wave conditions, calculating the design speed for various loading conditions, solving differential equations to obtain voyage time and distance, and relying on Granville's similarity law to calculate frictional resistance and loads due to wind and waves for ships with fouled hulls at design speed.
SHIPS AND OFFSHORE STRUCTURES
(2021)
Article
Physics, Applied
Tejaswi Josyula, Y. Esther Blesso Vidhya, Nilesh J. Vasa, Pallab Sinha Mahapatra, Arvind Pattamatta
Summary: Understanding the internal flow in evaporating sessile drops is crucial in various applications. This study reveals the nonaxisymmetric internal flow field caused by Marangoni flow at the liquid-vapor interface, and the transition to an axisymmetric toroidal flow during the evaporation process.
APPLIED PHYSICS LETTERS
(2022)
Article
Computer Science, Information Systems
G. Parvathy, Myneni Sukesh Babu, P. Sriram Karthick Raja, T. Thyagaraj, N. J. Vasa, R. Sarathi, Noureddine Harid, Huw Griffiths
Summary: The addition of lime to stabilize soil increases its strength and electrical properties, but pH and electrical conductivity decrease with longer curing periods. Analyzing mineralogical and micro-structural changes in the soil showed improvements in axial strength, plasma temperature, and electron number density with higher lime content and longer curing periods. Correlations between Ca II peaks in LIBS spectral data and lime content at different curing periods were successfully determined using PLSR technique with high accuracy.
Article
Physics, Multidisciplinary
Sneha Jayaganthan, Myneni Sukesh Babu, N. J. Vasa, R. Sarathi, Takahiro Imai
Summary: The conductivity of epoxy micro-nanocomposite specimens coated with different variants of coals is directly correlated with the carbon content of the coal samples. Using LIBS and machine learning techniques, the specimens were successfully classified, with Logistic regression method showing the highest training and testing accuracy of 100% and 98% respectively compared to other methods.
JOURNAL OF PHYSICS COMMUNICATIONS
(2021)
Article
Engineering, Multidisciplinary
Pabbati Vinod, Myneni Sukesh Babu, Ramanujam Sarathi, Nilesh J. Vasa, Stefan Kornhuber
Summary: Silicone rubber insulators were studied for contamination level using laser-induced breakdown spectroscopy (LIBS) analysis, successfully identifying salt deposits on the surface even at far distances and any time. The normalized intensity ratio of sodium peaks was used to evaluate the salt deposit density accurately.
IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS
(2022)
Article
Optics
Sooraj Shiby, Nilesh J. Vasa
Summary: This study reports a method for pulsed laser-assisted micro-scribing of Cu from dielectric material, with monitoring using laser-induced breakdown spectroscopy (LIBS). Multiple laser scans were needed for complete Cu removal, and the Cu I line intensity in the LIBS spectra decreased as the microchannel depth increased. Additionally, characteristic emission lines from substrate elements were observed in the LIBS spectra during the final laser scan process.
OPTICS AND LASER TECHNOLOGY
(2022)
Review
Materials Science, Multidisciplinary
A. Raja, Srinivasa Rakesh Cheethirala, Pallavi Gupta, Nilesh J. Vasa, R. Jayaganthan
Summary: This article reviews the interrelationship between LPBF process parameters, microstructure, crack initiation, and crack growth mechanisms under fatigue loading conditions. It highlights the importance of standardizing mechanical testing techniques, specimen design guidelines, and post-manufacturing treatments for improving the fatigue resistance of AlSi10Mg alloy. The influence of microstructural features and post-processing conditions on fatigue properties is discussed, along with the crack growth mechanism observed in LPBF processed material.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Materials Science, Multidisciplinary
Hemalaxmi Rajavelu, Nilesh J. Vasa, Satyanarayanan Seshadri
Summary: This study proposed and demonstrated the feasibility of a fiber-based LIBS technique for analyzing pulverized coal. By replacing the air medium with a hollow-core fiber, high-power laser pulses were effectively delivered to the target for ablation with a transmission efficiency of 50-60%. The addition of the hollow-core fiber upgraded the conventional LIBS technique into a remote characterization unit, as proven by the captured LIBS spectra.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
S. Sooraj, Y. R. Yugandhara, N. J. Vasa, A. Kavitha, S. Krishnan, M. Shigeki
Summary: In this study, the micro-scribing process of the Cu film on a dielectric substrate was investigated using lasers with different pulse durations. It was observed that the formation of recast layer near the microchannel occurred when using lasers with pulse durations of 6 ns and 500 ps, while no recast layer was observed when using lasers with pulse durations of 1 ps and 120 fs. XRD analysis revealed the presence of compressive residual stresses in the scribed region with the 6 ns and 500 ps lasers, and tensile residual stresses in the scribed region with the 1 ps and 120 fs lasers. Oxide layer formation was observed in all pulse regimes. A theoretical simulation was conducted to estimate the temperature on the dielectric substrate. Complete removal of Cu from the dielectric substrate would result in thermal damage. A hybrid micro-scribing technique, involving immersion in NaCl solution during the final laser scan, was demonstrated for nanosecond laser processing. Finally, a frequency selective surface (FSS) was fabricated using the hybrid scribing technique.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Sree Harsha Choutapalli, H. G. Prashantha Kumar, Emmanuel Paneerselvam, Nilesh J. Vasa, R. Jayaganthan
Summary: Fabrication of single-crystal silicon carbide thin films without impurities is crucial for microelectromechanical systems applications. Pulsed laser deposition combined with annealing can be used to grow 6H-SiC thin films at lower temperatures than conventional vapor deposition techniques. This study investigated the pulsed laser deposition of 6H-SiC thin films using two different silicon carbide targets and varying substrate temperatures. The results showed that smooth and continuous SiC film growth with low electrical resistance can be achieved using the reaction bonding technique.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2022)
Article
Engineering, Electrical & Electronic
Baskar Thangabalan, Neelmani, Neelesh J. Vasa, Ramanujam Sarathi, Noureddine Harid, Huw Griffiths
Summary: The present study investigates the effects of corona aging on the surface properties of silicone rubber alumina nanocomposites. The addition of alumina nanofiller improves the resistance to corona discharge, with an optimal filling amount. The samples exhibit a fast recovery in the first few hours after corona aging, and most of them regain their properties after about 8 hours of recovery time.
IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
(2022)
Article
Optics
Manish Chandra, Satyanarayanan Seshadri, Nilesh J. Vasa
Summary: This paper presents a dual-wavelength absorption-based approach for measuring and validating the steam dryness fraction of wet steam. The accuracy of the dryness measurement system using this optical method is determined to be +/- 1% for the range of dryness and operating pressure (1-10 bars) of wet steam.
Article
Engineering, Electrical & Electronic
K. Saran Kumar, Y. Esther Blesso Vidhya, Ramya Selvaraj, Satyanarayanan Seshadri, S. M. Shiva Nagendra, Nilesh J. Vasa
Summary: This article presents a dual-wavelength band broadband photoacoustic spectroscopy (BPAS) technique ideally suited to low-energy broadband sources for industrial and environmental multigas sensing applications. The proposed technique allows for comprehensive concentration measurement and eliminates the impact of cross sensitivity among gases. The MDL achieved for methane, ammonia, and carbon monoxide were 0.4 and 0.7 ppm, 0.3 and 1.8 ppm, and 2.6 ppm, respectively.
IEEE SENSORS JOURNAL
(2023)
Article
Engineering, Manufacturing
Y. Esther Blesso Vidhya, Nilesh J. Vasaa
Summary: Light-trapping is crucial for thin film solar cells, and the use of surface micro/nanostructures can improve light absorption. This study demonstrates the reduction of reflection and enhanced light trapping by fabricating random nanocones on a-Si thin film surfaces. Experimental results show a significant decrease in reflectance and good stability in thermal tests.
MANUFACTURING LETTERS
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
Sooraj Shiby, Yugandhara R. Yadam, Balamurugan T. Sivaprakasam, Kavitha Arunachalam, Nilesh J. Vasa
Summary: Micro-scale removal of Cu from a dielectric substrate using a hybrid technique of nanosecond laser-activated electrochemical micro-scribing has been demonstrated in this study. The technique successfully removed Cu from the dielectric material, improved surface morphology, and provided thermal protection.
LASER-BASED MICRO- AND NANOPROCESSING XVI
(2022)