An illustrated representation of the KISS exfoliation and photoemission experiment: 2D material is cleaved from the parent crystal due to superior interaction with the substrate. UV light is harnessed to photo-release electrons, enabling studies of electronic structure via direct visualization of the electronic bands, depicted in the backdrop. Credit goes to Antonija Grubišić-Čabo and Dina Maniar, from the University of Groningen.
Since the inception of graphene, a two-dimensional (2D) form of graphite, nearly twenty years ago, 2D materials have attracted a surge of interest owing to their distinctive physical traits. The original production of graphene employed adhesive tape to strip off layers from bulk graphite, a technique which, despite its Nobel-winning status, has certain shortcomings.
A collaborative team of international surface scientists has now designed a simple, yet effective, method to produce sizeable, high-purity 2D samples from a variety of materials using three different substrates. The team’s innovative approach, dubbed Kinetic In Situ Single-layer Synthesis (KISS), was elaborated recently in the journal Advanced Science.
2D materials possess physical properties absent in bulk material, largely due to charge carrier confinement. These 2D materials can be generated in two ways: by exfoliating a larger crystal or by growing a 2D layer. The exfoliation process, however, is labor-intensive, requiring specific skills and equipment, according to Antonija Grubišić-Čabo, a surface scientist at the University of Groningen (the Netherlands) and lead author of the Advanced Science paper. Moreover, it often produces tiny flakes and the adhesive tape used can leave polymer residues on their surfaces.
This image illustrates the setup for Kinetic In Situ Single-layer Synthesis (KISS). The bulk material is placed on a sample holder, regulated by a spring for impact (yellow arrow), and is pressed against a gold crystal (the brighter ring beneath the blue arrow). Once released, a 2D layer adheres to the gold substrate. Credit: Antonija Grubišić-Čabo, University of Groningen
Growing 2D films offers another alternative, providing the opportunity to generate large samples under controlled conditions. Yet, as Grubišić-Čabo mentions, perfecting the technique to grow such 2D materials can be time-consuming and might not always yield a flawless layer. With co-author Maciej Dendzik and a group of colleagues—many of whom have previously collaborated at Aarhus University (Denmark) as Ph.D. students—Grubišić-Čabo endeavored to develop a straightforward method for 2D materials production.
The team was aware of a few experiments utilizing gold films to exfoliate bulk material. Yet, these trials were primarily performed in air, rendering them unsuitable for air-sensitive materials or surface science research. The researchers sought a method that could produce air-sensitive 2D materials on an array of substrates. In their initial attempt, they used a gold crystal inside a high vacuum chamber and realized a thin 2D layer adhered nicely to the gold after slamming the crystal onto the bulk material. The exact reason for this is still unclear, but the team theorizes that the bond with the gold outstrengths the Van der Waals forces binding the layers in the bulk crystal.
Following this first experiment, the team improved their setup by adding a spring to the stage with the bulk material. This addition functioned as a shock absorber, allowing better control over the impact of the gold crystal. Moreover, they found silver and the semiconductor germanium could also serve as substrates for 2D material exfoliation. The team now uses single crystal gold thin films and they have the added benefit of being dissolvable, enabling the isolation of the 2D sample, as long as it is stable in air or liquid.
The KISS technique’s future applications include the development of devices from the 2D materials. While this isn’t yet feasible, the team is actively working towards it. The current KISS technique can generate clean, large 2D samples in an uncomplicated manner, even for air-sensitive 2D materials, utilizing standard laboratory equipment.
Reference: “In Situ Exfoliation Method of Large-Area 2D Materials” by Antonija Grubišić-Čabo, Matteo Michiardi, Charlotte E. Sanders, Marco Bianchi, Davide Curcio, Dibya Phuyal, Magnus H. Berntsen, Qinda Guo and Maciej Dendzik, 26 May 2023, Advanced Science.
DOI: 10.1002/advs.202301243
Table of Contents
Frequently Asked Questions (FAQs) about KISS Technique for 2D Materials
What is the KISS technique for producing 2D materials?
The KISS technique, short for Kinetic In Situ Single-layer Synthesis, is a straightforward method developed by a consortium of surface scientists. It involves using specific substrates, such as gold, silver, or germanium, to peel off large and pure 2D samples from different materials.
How does the KISS technique differ from the traditional adhesive tape method?
The traditional method of using adhesive tape to peel layers off bulk graphite, which led to the discovery of graphene, has limitations. The KISS technique offers a simpler and more efficient approach by utilizing specific substrates and controlled impact to generate clean and sizable 2D materials.
What are the advantages of using the KISS technique?
The KISS technique allows for the production of large, pure 2D samples in a straightforward manner. It can be applied to air-sensitive materials and provides better control over the resulting layers compared to other methods. Additionally, it utilizes standard equipment available in most surface science laboratories.
Can the KISS technique be used to build devices from 2D materials?
While the production of 2D materials using the KISS technique has been successful, the construction of devices from these materials is still under development. Researchers are actively working on utilizing the isolated 2D samples for future device fabrication.
What are the potential applications of the KISS technique?
The KISS technique opens doors for various applications in material science and surface science research. It enables the production of clean and pure 2D materials, which can be used in the development of advanced devices, electronics, and other technologies that leverage the unique properties of 2D materials.
More about KISS Technique for 2D Materials
- Advanced Science: In Situ Exfoliation Method of Large-Area 2D Materials
- University of Groningen: Antonija Grubišić-Čabo
- Aarhus University: Maciej Dendzik
3 comments
woah, KISS technique makin waves! simpliCity is key here. no fancy equipment needd, just standard stuff found in labs. excitin’ to see what devices they’ll make from these 2D materials. future is lookin’ bright!
KISS technique seems pritty practical! no more messy adhesiv tape method, yay! this methOd can make clean and large 2D samples, perfec for reserch and makin new stuff. hope they keep improving it!
wow! thIs Kiss techniq is so cool! i Luv how they cAn make big 2D materials so easy, like graffene. it’s like stikin’ a crystal on stuff an bam, u got a 2D layer. amazin! cant wait for them to build devicess!