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Q-carbon to Create Diamonds at Room Temperature - By : Luis Felipe Gerlein Reyes,

Q-carbon to Create Diamonds at Room Temperature


Luis Felipe Gerlein Reyes
Luis Felipe Gerlein Reyes Author profile
Luis Felipe Gerlein R. is a Ph.D. candidate at ÉTS. His research interests include nanofabrication and characterization of optoelectronic devices based on lead chalcogenides, carbon-based nanostructures and perovskite materials.

From natural diamonds to Q-carbon

Nature’s diamond factories works in very slow and complex processes to create those desirable precious stones.  In these, diamonds grow over the period of 1 billion to 3.3 billion years from carbon deposits.  It takes a pressure 150,000 times stronger than atmospherics’ pressure at sea level to turn graphite, the most stable form of carbon, into diamonds.

The GE diamond project devised a standardized procedure in 1941, to fabricate artificial diamonds by heating carbon to about 3000 °C under a pressure of 3.5 GigaPascals (GPa – 510,000 psi or 34,542 times the atmospheric pressure). Modern fabrication methods go as high as 5.5 GPa, working at temperatures of 1500 °C.

The Hope Diamond, the largest of all blue diamonds, 45.52 carats, exhibited at the National Museum of Natural History., United States.

The Hope Diamond, the largest of all blue diamonds, 45.52 carats, exhibited at the National Museum of Natural History., United States.

Q-carbon diamond fabrication process

These factors, besides others like their color and history, justify the high market price of diamonds.  However, this might be about to change with the report presented by scientists at North Carolina State University.  They have introduced a new stable phase of carbon, that can be obtained at room temperature allowing researchers to create artificial diamonds with possibly better properties than the ones found in nature.

Microdiamonds produced directly from a Q-Carbon substrate after the laser treatment. Taken from AIP/ALP Materials.

Microdiamonds produced directly from a Q-Carbon substrate after the laser treatment. Taken from AIP/ALP Materials.

This new carbon phase has been named Q-Carbon.  Its properties can also be tuned at room temperature by controlling the fabrication parameters, without changing the atmospheric pressure in the process.

According to the lead scientist of this project, Jay Narayan, Q-Carbon can be added to the list of existing solid phases of carbon, diamond and graphite. However, it may not be that easy to find it as frequently as the other two.  The places where Q-Carbon could only be found in a natural environment would be the nucleus of planets.  Using Q-Carbon to create artificial diamonds presents a monocrystalline structure, making it readily stronger than common polycrystalline materials.

The fabrication process does not require a superheated chamber; it takes place at room temperature. It starts with a layer non-crystalline amorphous carbon coating a substrate of sapphire, glass or plastic polymer.   Then, a highly energetic laser pulse, of a duration of 200 nanoseconds blasts this carbon layer, rapidly rising its temperature to about 4000K or 3,727 °C.  Right after, the it quickly cools down giving way to a new unique crystalline form, and controlling the cooling rate, diamond structures are produced.

“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.  They also noted how by changing the laser pulse duration and substrate type, the final product can be altered. Besides producing monocrystalline carbon, other non-diamond structures shapes have been found in their experiments.

This process is relatively low-cost.  The diamond produced within the Q-carbon is harder than natural diamond, displays ferromagnetic abilities (something completely new) and glows under low levels of energy. There are many properties and applications yet to be discovered and the potential for this new material is only starting to reveal.

The authors consider potential applications of this technique to create large area diamond sheets useful in the pharmacological industry, updating industrial processes based on artificial diamonds and complex nanostructures like diamond nanodots or microneedles.

Research articles

This work has been published in two research articles:

  1. “Novel Phase of Carbon, Ferromagnetism and Conversion into Diamond” can be found here.
  2. The second report “Direct conversion of amorphous carbon into diamond at ambient pressures and temperatures in air” can be found here.

 

Luis Felipe Gerlein Reyes

Author's profile

Luis Felipe Gerlein R. is a Ph.D. candidate at ÉTS. His research interests include nanofabrication and characterization of optoelectronic devices based on lead chalcogenides, carbon-based nanostructures and perovskite materials.

Program : Electrical Engineering 

Research chair : Canada Research Chair in Printed Hybrid Optoelectronic Materials and Devices 

Author profile


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