New graphene technology: visualize the grain boundaries, high-quality graphene film batch preparation is no longer difficult!

As of now, large-scale mass production of graphene films while controlling and maintaining their excellent performance without compromise is still an unrealized challenge. One of the main problems is that graphene will form a “grain boundary” during the growth process, and its excellent performance will be greatly reduced due to the existence of grain boundary defects. Recently, a team in Sweden and Germany developed a new technology that allows simple, rapid and large-scale observation of line defects generated during the growth of graphene materials. The study was published in “Scientific Progress”.

The list of possible applications for graphene covers almost every aspect of future technologies, including technologies that address energy and health issues such as transistors, sensors, energy stores, flexible electronics, biomedical, etc. Take advantage of its outstanding mechanical, electrical, thermal and optical properties.

 New graphene technology: visualize grain boundaries, batch production of high quality graphene films is no longer difficult!

The measure of the conductivity of any conductor is how easily carriers, such as electrons or ions, pass through it. At this point, graphene is amazing, and its carrier mobility is the highest of all current materials. Graphene is considered one of the most promising materials in a range of applications due to its excellent properties. However, when a large area of ​​graphene film is synthesized, its ultrahigh electron mobility is greatly reduced due to the presence of grain boundary defects.

 New graphene technology: visualize grain boundaries, batch production of high quality graphene films is no longer difficult!

As of now, large-scale mass production of graphene films while controlling and maintaining their excellent performance without compromise is still an unrealized challenge. One of the main problems is that graphene forms a so-called “grain boundary” during the growth process. When a graphene sheet is synthesized by chemical vapor deposition (CVD) (usually in the vicinity of 100 mm × 100 mm or 150 mm × 150 mm), graphite is used. Defective deposits occur in the olefinic material. Recently, a team in Sweden and Germany developed a new technology that allows simple, rapid and large-scale observation of line defects generated during the growth of graphene materials. The study was published in “Scientific Progress”.

The first author of the study, Xu Gefan, a Ph.D. student at the KTH Royal Institute of Technology in Stockholm, said that these grain boundaries, as their name suggests, are tiny connections in the two-dimensional honeycomb lattice pattern of graphene. These seams impede the flow of electrons and severely affect the performance of graphene materials. “It’s like the seams of patchwork quilts,” Fan said. “They are inevitable, and now we have to tolerate their existence.”

With proper visualization of the graphene grain boundaries, scientists can gain a lot of control in these inevitable defects. Fan said that the study provides a way to effectively and efficiently observe the grain boundary size and using the fab’s standard process, namely vapor hydrofluoric acid (VHF) etching and optical microscopy. distributed.

Fan said: “So far, there is no simpler, faster and scalable method for this method to display large-area CVD graphene on silicon dioxide (SiO2) substrates. The grain boundary.

Fan said that this method may help speed up the process of developing large-scale high-quality graphene synthesis. “It provides a rapid assessment of the grain boundary density of large-area graphene samples. The evaluation process can take up to two minutes,” he said.

“It can also be used for post-mortem analysis of emerging graphite devices (such as pressure sensors, transistors and gas sensors) using graphene patches. To study the effect of grain boundary defects on device performance.