The new CVD process to prepare graphene only needs 50 ℃

       Recently, researchers from Japan and Taiwan created a new CVD method that uses graded methane vapor sources and molten gallium catalysts to grow graphene at temperatures as low as 50 ° C. The research is a significant advance in the synthesis of low-temperature graphene. For the first time, researchers have grown graphene directly onto plastic substrates. In the future, graphene can be incorporated into a variety of electronic devices.

As we all know, CVD method is currently the most efficient method for preparing high-quality monolayer large area graphene film, but the current process requires high temperature above 1000 ℃, the cost is high and the process is complicated. Recently, a team of researchers from Japan and Taiwan created a new CVD method that uses graded methane vapor sources and molten gallium catalysts to grow graphene at temperatures as low as 50 ° C. The findings were published in the recent issue of Scientific reports in Nature.

      Lowering the CVD synthesis temperature of graphene can excellently integrate graphene into various applications, such as directly integrating CVD grown graphene into an electronic device.

      The team explained that in silicon-based electronics, the maximum temperature at which the module can withstand the integration of graphene is about 400 ° C. Plastic semiconductor devices have even lower thresholds and can withstand temperatures as high as 100 ° C during graphene growth. Graphene growth occurs near 1000 ° C under conventional CVD techniques and is not suitable for direct integration into electronic devices.

 This new approach breaks the limitation. The team chose molten gallium as a catalyst to grow CVD graphene on sapphire and polycarbonate substrates with the help of a dilute methane atmosphere, and the temperature required could be reduced to about 50 ° C. Gallium is chosen as a catalyst as it is a catalyst that has proven to be effective in recent graphene growth processes and can be easily removed by gas jets after the synthesis of graphene. Carbon source is the use of air and nitrogen and argon mixture diluted to 5% methane gas.

The researchers examined the quality of the graphene grown using Raman spectroscopy, scanning electron microscopy and high-resolution transmission electron microscopy. Characterization results show that the new CVD process is capable of growing high quality graphene at relatively near room temperature, with graphene grown on polycarbonate substrates and sapphire substrates at 50 ° C and 100 ° C, respectively.