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

Feb. 14, 2014

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.

John Wallace

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.