Processes for non-destructive transfer of graphene for industrial production

Since the discovery of graphene in 2004, research on how to make graphene useful in industrial applications has been fervent. Graphene has many desirable properties:

• It’s the strongest material—it’s over two hundred times stronger than steel.
• It’s thin—just one gram of graphene can cover an entire football field.
• It’s conductive—it’s even more conductive than copper.

Due to these attributes, the potential applications and areas of application seem endless—from electronics to the solar industry to the field of medicine. But to take graphene from the lab bench to the boardroom is still a major challenge, especially when it comes to costs, as it is with most cutting-edge technologies discovered in universities and research groups.

Researchers from the University of San Diego have explored methods for the non-destructive transfer of graphene. This isn’t a new exploration, as researchers have been investigating methods of graphene synthesis and transfer since graphene’s discovery in 2004.

The four main barriers that have prevented the large scale of production of graphene have been cost, the lack of a speedier process, toxic waste from graphene production, and successfully transferring graphene without defects. Current methods for synthesizing high-quality graphene as single layers take a long time and are toxic, but they have their advantages and challenges.

Silicon-Carbide Epitaxy

Silicon-carbide (SiC) epitaxy involves heating a SiC wafer in a vacuum or in an argon atmosphere to temperatures above 2000 degrees Celsius. Silicon atoms sublimate from the crystal, leaving carbon which become graphene. This has been demonstrated with single and multiple layers of graphene.

One key advantage of this method is that graphene can cover the whole surface of an insulating wafer, affording high electron mobilities and desirable for integrated circuits.

The Chemical Vapor Disposition of Graphene

The chemical vapor disposition (CVD) of graphene makes graphene very versatile, also offering both single and multiple layers of graphene on a variety of substrates. Many studies have been done on copper since it’s relatively inexpensive. The CVD method can also be performed in a vacuum or at atmospheric pressure—but not nearly at high of temperature as SiC epitaxy (as low as 300 degrees Celsius).

Current Methods of Graphene Transfer

Typically, graphene has to be synthesized onto copper, through CVD, and then transferred onto the desired substrate. This process requires graphene being supported onto polymeric film and then etching copper foil with a corrosive medium. This method is both costly in time and in efficiency, requiring 300 kilograms of copper for just one gram of graphene. So graphene production through current methods only makes sense for research purposes.

Transferring Graphene Non-Destructively Needs More Development

University of San Diego researchers explored two specific methods of graphene transfer—from single-crystalline wafers and from copper foil. Through their review, it was concluded that some methods may be better for smaller, chip-scale production, while other methods could be used for larger, industrial scale, roll-to-roll production. Further research and development is necessary to overcome obstacles such as toxic waste and the relative lack of speed in the fabrication process.

Graphene as a wonder material still has immense promise for the future. If you’re looking for graphene sheets for sale or CVD graphene, contact us today to see how we can meet your graphene needs.