Researchers have discovered a new phase of solid carbon, which they have named Q-carbon. The discovery is different from all known phases of graphite and diamond. Not only did they discover it, they have developed a technique using Q-carbon to make diamond-related structures at room temperature, and at ambient atmospheric pressure in air.
According to North Carolina State University: “Phases are distinct forms of the same material; there were only two known solid phases of carbon: graphite and diamond. But the researchers have now revealed an entirely new, rare phase.”
Jay Narayan, the John C. Fan Distinguished Chair Professor of Materials Science and Engineering at N.C. State, and lead author of three papers, including one published in the Journal of Applied Physics describing the work, said in a statement: “We’ve now created a third solid phase of carbon.”
‘The only place it may be found in the natural world would be possibly in the core of some planets.’
“Not only is it a novel phase of matter, it has some exciting characteristics; for example, Q-carbon glows when exposed to even low levels of energy and is harder than diamond. “Q-carbon’s strength and low work-function — its willingness to release electrons — make it very promising for developing new electronic display technologies,” Narayan said.
And not only that, it’s also ferromagnetic, which neither diamond nor graphite are. “We didn’t even think that was possible,” adds Narayan.
In a statement from the University, the researchers explain that Q-carbon could also be used to create a variety of single-crystal diamond objects. “To understand that, you have to understand the process for creating Q-carbon.
“Researchers start with a substrate, such as sapphire, glass, or a plastic polymer. The substrate is then coated with amorphous carbon — elemental carbon that, unlike graphite or diamond, does not have a regular, well-defined crystalline structure. The carbon is then hit with a single laser pulse lasting approximately 200 nanoseconds.
“During this pulse, the temperature of the carbon is raised to 4,000 Kelvin (or around 3,727 degrees Celsius) and then rapidly cooled. This operation takes place at one atmosphere — the same pressure as the surrounding air.
“The end result is a film of Q-carbon, and researchers can control the process to make films between 20 nanometers and 500 nanometers thick.
“By using different substrates and changing the duration of the laser pulse, the researchers can also control how quickly the carbon cools. By changing the rate of cooling, they are able to create diamond structures within the Q-carbon.”
“We can create diamond nano-needles or micro-needles, nano-dots, or large-area diamond films, with applications for drug delivery, industrial processes, and for creating high-temperature switches and power electronics.
“These diamond objects have a single-crystalline structure, making them stronger than poly-crystalline materials. And it is all done at room temperature and at ambient atmosphere — we’re basically using a laser like the ones used for laser eye surgery. So, not only does this allow us to develop new applications, but the process itself is relatively inexpensive,” Narayan said.
By repeating the laser-pulse/cooling process, researchers are able to convert more of the Q-carbon into diamond. According to the University, if Q-carbon is harder than diamond, why would someone want to make diamond nano-dots instead of Q-carbon ones? Because we still have a lot to learn about this new material.
“We can make Q-carbon films, and we’re learning its properties, but we are still in the early stages of understanding how to manipulate it.
“We know a lot about diamond, so we can make diamond nano-dots. We don’t yet know how to make Q-carbon nano-dots or micro-needles. That’s something we’re working on,” Narayan said.
The university has filed for provisional patents on the techniques for creating Q-carbon, and the diamond creation techniques.