Scientists at the Oak Ridge National Laboratory of the Department of Energy found that the key element that determines the dimensions of graphene is hydrogen and not carbon.
The research was conducted by a team consisting of a professor of Chemistry at New Mexico State University, Sergei Smirnov, and Ivan Vlassiouk of ORNL. Details of the research were published in ACS Nano journal.
Graphene grains come in several different shapes. Hydrogen gas controls the grains' appearance.
Vlassiouk stated that hydrogen triggers the growth of graphene and impacts its size and shape. He said that they have formulated a technique to grow hexagonal shaped graphene grains resulting in the formation of flawless single crystals.
In the past, graphene was grown by decomposing carbon-containing gases positioned on a copper foil under high temperature conditions. This process of growing graphene was known as chemical vapor deposition. To manufacture graphene films of high-quality, they had to understand the growth phenomenon in a better way. Fully grown graphene films comprise graphene grains of various sizes and shapes.
Vlassiouk stated that the rate of growth, the size and shape of graphene grains was not only affected by carbon source and substrate but was mainly affected by hydrogen. He added that hydrogen activates the adsorbed molecules to begin graphene growth and to remove weak bonds at the ends of the graphene grains.
Vlassiouk and co-workers have developed a large scale method to create graphene. The method enables them to manipulate boundaries and grain size that will enhance graphene’s utility in semiconductors, transistors and electronic devices.
Vlassiouk stated that the research will be useful for the growth of single domain graphene on a mass scale that will amount to a major innovation for implementing graphene in real-world equipment.
Source: http://www.ornl.gov/