by Alfredo Carpineti
Scientists from North Carolina State University have discovered a new form of solid carbon, called Q-carbon, and it has some unusual properties: Q-carbon is ferromagnetic, harder than diamond, and glows when exposed to energy. These properties make it different fromgraphite and diamond
(the other two possible forms of solid carbon, known as phases), and the researchers discovered that Q-carbon can be used to construct diamond structures at room temperature.
(the other two possible forms of solid carbon, known as phases), and the researchers discovered that Q-carbon can be used to construct diamond structures at room temperature.
To create Q-carbon, it's necessary to have two things: a source of carbon and a substrate, a material where the reaction can take place. The source is called amorphous carbon, where all the atoms are in a disorganized, irregular distribution. Coal is an example of amorphous carbon, while in this case the choice for the substrate was between sapphire, glass or plastic.
The substrate was coated in a layer of amorphous carbon, and was then hit with a single laser pulse for about 200 nanoseconds, heating it to 4,000 Kelvins (3,726 °C; 6,740 °F). The carbon was then rapidly cooled down, causing it to crystalize into Q-carbon.
“We’ve now created a third solid phase of carbon,” said Jay Narayan, lead author of three papers describing the work, in a statement. “The only place it may be found in the natural world would be possibly in the core of some planets.”
So far, Q-carbon has been produced in films between 20 to 500 nanometers thick. The researchers have a lot of control in the creation of Q-carbon, and by changing the substrate or the pulse length, they were able to create diamond nanostructures within the new material.
Shown is a scanning electron microscopy image of microdiamonds made with the new technique. NCSU
“We can create diamond nanoneedles or microneedles, nanodots, or large-area diamond films, with applications for drug delivery, industrial processes and for creating high-temperature switches and power electronics,” Narayan said.
“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.”
If a cheap, large-scale method of production is found, the unusual properties of Q-carbon could make it a phenomenal material to be used in the tech industry. Beyond being hard and durable, the material's response to magnetic and light impulses is very promising in the development of new electronic displays.
The most recent paper is published in the Journal of Applied Physics, while the one on diamond nano-crystals was published in October by APL Materials.
