Illustration of a graphene movie being hole-drilled by laser irradiation. Scientists at Tohoku University used a femtosecond laser to effectively micro/nanofabricate graphene films, developing multi-point holes without damage and eliminating contaminants. (b) Formation of 32 laser areas on the graphene movie. By using this method to an ultra-thin atomic layer of graphene, the very same group has actually now prospered in performing a multi-point hole drilling without damaging the graphene film. Upon closer assessment of the areas irradiated with low-energy laser pulses, which did not make holes, via a high-performance electron microscopic lense, Uesugi and his colleagues found that pollutants on the graphene had actually also been removed.
Back in January, Tohoku University researchers created a method that could micro/nanofabricate silicon nitride thin gadgets with thicknesses varying from 5 to 50 nanometers. The technique utilized a femtosecond laser, which released exceptionally short, rapid pulses of light. It turned out to be efficient in quickly and easily processing thin products without a vacuum environment.
( a) Schematic of the laser processing system. (b) Formation of 32 laser spots on the graphene movie. (c) Image of a graphene movie that has actually been multi-point hole-drilled. Credit: Yuuki Uesugi et al
. By applying this technique to an ultra-thin atomic layer of graphene, the same group has actually now been successful in carrying out a multi-point hole drilling without harming the graphene movie. Details of their development were reported in the journal Nano Letters on May 16, 2023.
” With appropriate control of the input energy and number of laser shots, we had the ability to carry out precise machining and develop holes with sizes varying from 70 nanometers– much smaller sized than the laser wavelength of 520 nanometers– to over 1 millimeter,” states Yuuki Uesugi, assistant teacher at Tohoku Universitys Institute of Multidisciplinary Research for Advanced Materials, and co-author of the paper.
Picture of laser-processed graphene film observed by scanning transmission electron microscopy. The black areas suggest through-holes. The white things suggest surface pollutants. Credit: Yuuki Uesugi et al
. Upon closer evaluation of the areas irradiated with low-energy laser pulses, which did not make holes, via a high-performance electron microscope, Uesugi and his colleagues discovered that pollutants on the graphene had actually also been removed. Further magnified observation revealed nanopores less than 10 nanometers in diameter and atomic-level defects, where several carbon atoms were missing out on in the crystal structures of the graphene.
Atomic flaws in graphene are both helpful and destructive, depending on the application. Whilst flaws often downgrade certain residential or commercial properties, they also introduce brand-new functionalities or improve particular attributes.
Credit: Yuuki Uesugi et al.
” Observing a tendency propensity the density of nanopores and defects flaws increase proportionally with the energy and number of laser shots led us to conclude the formation of nanopores and defects could be manipulated controlled using a femtosecond laser irradiation,” adds Uesugi. “By forming nanopores and atomic-level problems in graphene, not just can electrical conductivity be managed but also quantum-level qualities such as spin and valley. The impurity elimination by femtosecond laser irradiation discovered in this research might develop a new method for non-destructively and easily washing high-purity graphene.”
Looking ahead, the team intends to develop a cleaning technique using the laser and bring an in-depth examination into how to carry out atomic problem formation. Additional developments will have a huge effect on locations from quantum products research to biosensor development.
Reference: “Nanoprocessing of Self-Suspended Monolayer Graphene and Defect Formation by Femtosecond-Laser Irradiation” by Naohiro Kadoguchi, Yuuki Uesugi, Makoto Nagasako, Tetsuro Kobayashi, Yuichi Kozawa and Shunichi Sato, 16 May 2023, Nano Letters.DOI: 10.1021/ acs.nanolett.3 c00594.
Illustration of a graphene movie being hole-drilled by laser irradiation. The size of the carbon atoms is overstated and varies from the real size. Credit: Yuuki Uesugi et al
. Researchers at Tohoku University utilized a femtosecond laser to effectively micro/nanofabricate graphene films, developing multi-point holes without damage and getting rid of pollutants. The method might replace standard, more complex methods, offering prospective improvements in quantum products research study and biosensor development.
Found in 2004, graphene has revolutionized different scientific fields. It has impressive properties like high electron mobility, mechanical strength, and thermal conductivity. Extensive effort and time have actually been invested in exploring its possible as a next-generation semiconductor product, causing the advancement of graphene-based transistors, transparent electrodes, and sensors.
But to render these gadgets into practical application, its crucial to have efficient processing strategies that can structure graphene films at micrometer and nanometer scale. Normally, micro/nanoscale material processing and gadget manufacturing use nanolithography and focused ion beam methods. However, these have actually posed longstanding challenges for laboratory researchers due to their need for massive equipment, lengthy production times, and complicated operations.
