Since the discovery of two-dimensional graphite (called graphene) nearly two decades ago, interest in 2D materials with their physical properties has exploded. Famously, graphene is produced by scraping loose graphite with adhesive tape. Although it is good for the Nobel Prize, this method has its drawbacks. An international group of topographical experts has developed a simple method (Easily create great clean 2D objects – just KISS) to create large, high-quality 2D models from different materials using three different materials. Their method, kinetic in situ single-layer synthesis (KISS) was described in the journal Advanced Science on June 1.
2D objects have physical properties that bulk objects do not share. Lockdown of carriers is one of the reasons. There are two ways to create these 2D objects: remove large crystals or grow a 2D layer. Removal involves removing large layers of crystals until you are left with only one layer.
“This process takes time and requires specific skills and equipment,” says Antonija Grubisic-Cabo, a geoscientist at the University of Groningen (Netherlands) and the first author of a high-tech paper on say. “Also, small flakes often appear, where the tape used can leave polymer on them.”
Gold
Developing 2D movies is another way. This allows the creation of large samples under controlled conditions. “However, it often takes a long time to find out how to grow such 2D objects. This process does not always result in a large layer,” Grubic-Cabo says. Together with the late author Maciej Dendzik, he brought together his “dream” colleagues, many of whom worked together at the University of Aarhus (Denmark) as PhD students, to develop a simple method for creating 2D objects.
We know of some experiments in which gold films were used to annihilate large objects. But these are usually done in air, which means that this method is not suitable for sensitive objects or advanced scientific research. The team wanted a system that would allow the creation of 2D objects with atmospheric effects and multiple objects.
In their first attempt, they used gold crystals in the upper room. “We put the crystal on a large scale and saw a beautiful 2D layer sticking to the gold.” The reason for this is unclear, but the team suspects that the gold bonds are stronger than the Van der Waals forces that hold the layers and loose crystals together.
Tools
They used this first experience, adding liquid to the stage and negative elements that act as a complex and thus allow better control of the effect of the gold crystal. Additionally, the group demonstrated that semiconducting silver and germanium can be used as substrates to eliminate 2D objects. “Gold crystals are a standard feature of advanced scientific laboratories, where they are used in the design of instruments, for example.
Scientists do not like to break these crystals, but that did not happen in these experiments, “Grubisic-Cabo says. “But we have changed the process to use a thin film of crystal gold. This has the added benefit of being able to dissolve the gold so we can separate the 2D sample, as long as it is stable in air or liquid.
These isolated samples can be used for the next step: a device building from 2D objects that will be created using the KISS process. “It’s impossible, but we’re working on it,” Grubisic-Cabo says. “So what we have is a process to create large, clean 2D samples in a very simple way, which allows us to create 2D objects with an air effect. In addition, our process uses standard equipment that is available in any scientific laboratory.
Source: University of Groningen
