• Semiconductor crystals form 'artificial graphene' with potential for lasers, LEDs

    Researchers from the University of Luxembourg, the IEMN-Department of ISEN (Lille, France), Max-Planck-Institut für Physik komplexer Systeme (Dresden, Germany), and the University of Utrecht (Utrecht, The Netherlands) have done a theoretical study of what is called "artificial graphene" -- a 2D hexagonal sheet of matter that, rather than graphene's carbon, is made of nanocrystals of traditional semiconductor materials.
    Feb. 14, 2014
    (Credits: left, University of Luxembourg; right, copyright Physics and Materials Science Research Unit 2014)
    In conventional graphene, carbon atoms form a 2D hexagonal lattice (left). In artificial graphene, semiconductor nanocrystals form the points in the lattice (right). In this particular case, each nanocrystal has the shape of a rhombicuboctahedron (which has 14 squares and eight triangles).
    In conventional graphene, carbon atoms form a 2D hexagonal lattice (left). In artificial graphene, semiconductor nanocrystals form the points in the lattice (right). In this particular case, each nanocrystal has the shape of a rhombicuboctahedron (which has 14 squares and eight triangles).

    Walferdange, Luxembourg--Researchers from the University of Luxembourg, the IEMN-Department of ISEN (Lille, France), Max-Planck-Institut für Physik komplexer Systeme (Dresden, Germany), and the University of Utrecht (Utrecht, The Netherlands) have done a theoretical study of what is called "artificial graphene" -- a 2D hexagonal sheet of matter that, rather than graphene's carbon, is made of nanocrystals of traditional semiconductor materials.1 They believe that artificial graphene has potential for use in lasers, LEDs, and photovoltaics, as well as in electronics.

    The researchers studied structures with a lattice period of below 10 nm, finding that they can have conventional semiconductor properties combined with so-called Dirac bands (which, in graphene, lead to ballistic electrons). Semiconductors in the study included rocksalt lead chalcogenides and zinc-blende cadmium chalcogenide.

    Advances in colloidal assembly will allow artificial graphene to be fabricated, say the researchers. "Artificial graphene opens the door to a wide variety of materials with variable nanogeometry and tunable properties," notes University of Luxembourg scientist Efterpi Kalesaki.

    REFERENCE:

    1. E. Kalesaki et al., Physical Review Letters (2014); doi: 10.1103/PhysRevX.4.011010

    About the Author

    John Wallace

    Senior Technical Editor (1998-2022)

    John Wallace was with Laser Focus World for nearly 25 years, retiring in late June 2022. He obtained a bachelor's degree in mechanical engineering and physics at Rutgers University and a master's in optical engineering at the University of Rochester. Before becoming an editor, John worked as an engineer at RCA, Exxon, Eastman Kodak, and GCA Corporation.

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