Breakthrough in Graphene Nanoprocessing Using a Femtosecond Laser
Researchers at Tohoku University have achieved a significant advancement in the field of graphene nanoprocessing by successfully fabricating micro and nanoscale holes in graphene films using a femtosecond laser. This groundbreaking technique offers a promising alternative to complex traditional methods, opening doors for quantum materials research and biosensor development.
Since its discovery in 2004, graphene has revolutionized scientific disciplines due to its exceptional properties, including high electron mobility, mechanical strength, and thermal conductivity. Scientists have invested considerable time and effort in exploring its potential as a next-generation semiconductor material, leading to the development of graphene-based transistors, transparent electrodes, and sensors.
However, to translate these devices into practical applications, efficient processing techniques for structuring graphene films at the micrometer and nanometer scale are essential. Conventional approaches rely on nanolithography and focused ion beam methods, which pose challenges for laboratory researchers due to their reliance on large-scale equipment, lengthy manufacturing times, and complex operations.
Earlier this year, the researchers at Tohoku University developed a technique to fabricate micro and nanoscale silicon nitride thin devices with thicknesses ranging from 5 to 50 nanometers. This method employed a femtosecond laser, emitting extremely short and rapid pulses of light, enabling convenient and rapid processing of thin materials without the need for a vacuum environment.
Building on this success, the same research group has now achieved multi-point hole drilling in an ultra-thin atomic layer of graphene without damaging the film. The breakthrough was reported in the journal Nano Letters on May 16, 2023.
“We were able to achieve precise machining and create holes with diameters ranging from 70 nanometers to over 1 millimeter by controlling the input energy and the number of laser shots,” explains Yuuki Uesugi, co-author of the paper and an assistant professor at Tohoku University’s Institute of Multidisciplinary Research for Advanced Materials.
In addition to creating holes, the researchers found that low-energy laser pulses also removed contaminants from the graphene film when examined under a high-performance electron microscope. Further examination revealed nanopores with diameters less than 10 nanometers and atomic-level defects in the crystal structures of the graphene, where several carbon atoms were missing.
While atomic defects in graphene can be both detrimental and advantageous, depending on the application, this research demonstrates that the formation of nanopores and defects can be controlled through femtosecond laser irradiation. Manipulating the graphene in this way not only allows for the control of electrical conductivity but also opens up possibilities for controlling quantum-level characteristics such as spin and valley.
Furthermore, the discovery of contaminant removal through femtosecond laser irradiation offers a potential method for non-destructively and cleanly washing high-purity graphene, which could have significant implications in the field.
Moving forward, the research team aims to develop a cleaning technique using the femtosecond laser and conduct an in-depth investigation into the formation of atomic defects. These advancements hold great promise for quantum materials research and 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.3c00594
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Frequently Asked Questions (FAQs) about graphene nanoprocessing
What is graphene nanoprocessing?
Graphene nanoprocessing refers to the fabrication and structuring of graphene films at the micro and nanoscale. It involves techniques and methods to create precise patterns, holes, and structures in graphene using various tools and technologies.
How is femtosecond laser used in graphene nanoprocessing?
Femtosecond lasers emit extremely short and rapid pulses of light. In graphene nanoprocessing, these lasers are used to perform precise machining and create holes in graphene films. By controlling the input energy and number of laser shots, researchers can manipulate the size and shape of the holes without damaging the graphene.
What are the advantages of graphene nanoprocessing with a femtosecond laser?
Graphene nanoprocessing with a femtosecond laser offers several advantages. It provides a simpler and more efficient method compared to traditional techniques, eliminating the need for large-scale equipment and reducing manufacturing times. The technique enables precise control over the structure of graphene at the micro and nanoscale, opening up possibilities for advancements in quantum materials research and biosensor development.
Can graphene nanoprocessing improve the purity of graphene?
Yes, graphene nanoprocessing can help improve the purity of graphene. The technique using a femtosecond laser not only creates holes and structures but also removes contaminants from the graphene film. This results in cleaner, high-purity graphene, which is important for various applications where the quality and integrity of the graphene material are crucial.
What are the potential applications of this graphene nanoprocessing technique?
The graphene nanoprocessing technique using a femtosecond laser has wide-ranging potential applications. It can be utilized in quantum materials research to manipulate electrical conductivity and control quantum-level characteristics. In biosensor development, it offers possibilities for creating precise structures and enhancing sensor performance. Additionally, the technique can contribute to advancements in semiconductor devices, transparent electrodes, and other graphene-based technologies.
More about graphene nanoprocessing
- Tohoku University: Tohoku University
- Nano Letters Journal: Nano Letters
- “Nanoprocessing of Self-Suspended Monolayer Graphene and Defect Formation by Femtosecond-Laser Irradiation” research paper: Research Paper
