Scientists let you find electrified diamonds

Research by an international team of scientists led by Nanyang Technological University (NTU Singapore) and Massachusetts Institute of Technology (NTU Singapore) in Singapore predicts that diamonds will transform into nanoscale strain and generate electricity like metals. It may conduct.MIT), USA.

Using computer simulations, a team that also includes researchers from the Russian Institute of Science and Technology (Skoltech) found that mechanical strain applied to nanoscale diamond needles could reversibly change its shape. This was shown as an early proof of concept. Their electrical properties give them metal-like conductivity at room temperature and pressure.

Studies published in the journal Proceedings of the United States Academy of Sciences October 6, 2020 has the potential to lead to future applications of power electronics used in a variety of machines, from automobiles and appliances to smart grids. High-efficiency light-emitting diodes (LEDs); optical devices; quantum sensing enhances and improves what sensors can do today.

The corresponding authors of this study are NTU President Subra Thresh, MIT Professor Ju Li, and MIT Senior Researcher Ming Dao. The list of authors includes MIT graduate student Zhe Shi and Skoltech professors Evgenii Tsymbalov and Alexander Shapeev.

The discovery was an experimental discovery by a team of NTU-Hong Kong-MIT scientists led by Professor Suresh who reported diamond nanoneedles (each about 1000 times thinner than human hair) in a 2018 paper published in Science. It follows. It can be bent and stretched significantly, so it snaps back undamaged when the strain is released.

The extremely high hardness and stiffness of diamond, and its many extreme physical properties, make diamond a good candidate for a variety of applications. New discoveries also pave the way for new applications of diamonds in the fields of quantum information, power electronics, and photonics, including quantum sensors, high-efficiency photodetector and emitter designs, and applications in biomedical imaging. ..

Professor Suresh, who is also a professor at NTU Distinguished University, said: “The ability to design and design diamond conductivity without changing its chemical composition or stability provides unprecedented flexibility for custom designing that function. The method demonstrated in this study is: Through strain engineering, it can be applied to a wide range of other semiconductor materials of technical interest in mechanical, microelectronics, biomedical, energy, and photonics applications. “

From insulators to conductors like metals

A material that easily conducts current is called a conductor, and a material that does not conduct current, such as diamond, is called an insulator.

Most forms of diamond are excellent electrical insulators due to their ultra-wide bandgap of 5.6 electron volts (eV). This means that a large amount of energy is required to excite the electrons in the material before they can act as carriers of electric current. The smaller the bandgap, the easier it is for current to flow.

Using computer simulations, including quantum mechanics, mechanical deformation analysis, and machine learning, scientists have created this bandgap by elastically deforming diamond nanoneedles by bending the diamond probe to push it from the side. I found that it can be narrowed.

They showed that the expected bandgap narrowed as the strain on the diamond nanoneedle increased. This indicates high electrical conductivity. The bandgap disappeared completely near the maximum amount of strain that the needle could withstand before it broke. They further showed that such metallization of diamond on a nanoscale can be achieved without causing phonon instability or a phase transition from diamond to graphite, the soft material of pencils.

The researchers then used the simulation results to train machine learning algorithms to identify common conditions for achieving optimum conductivity of nanoscale diamonds in various geometries. This scientific study is still in its infancy and offers the opportunity to further develop potential devices with unprecedented characteristics and performance.

Co-author, Professor JuLi of MIT, said: “We have found that it is possible to reduce the bandgap from 5.6 eV to zero. The point of this is that if it can be changed continuously from 5.6 to zero eV, it will cover the entire range of the bandgap. Strain engineering allows diamonds to have a bandgap of silicon, which is the most widely used semiconductor, and gallium nitride, which is used in LEDs. Infrared detectors can also be used from infrared to ultraviolet in the spectrum. It can also detect the entire range of light up to the part. “

For more information on this study, read Turn Diamonds into Metals.

See also: “Diamond Metallization” by Zhe Shi, Ming Dao, Evgenii Tsymbalov, Alexander Shapeev, Ju Li, Subra Suresh, October 5, 2020, Minutes of the National Academy of Sciences..
DOI: 10.1073 / pnas.2013565117

Scientists let you find electrified diamonds

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