Columbia University (New York, NY) engineers, working in partnership with Princeton University (Princeton, NJ), Purdue University (West Lafayette, IN), and Istituto Italiano di Tecnologia (Genova, Italy), have engineered “artificial graphene” by recreating its structure in a semiconductor quantum-well device. Compared to the fixed position of atoms in natural graphene, the artificial graphene can be engineered with different atomic spacings and lattice configurations, making it highly versatile for condensed-matter research and other areas of optoelectronics that hold promise for graphene materials, including information processing and novel semiconductor switches and transistors.
To fabricate the artificial graphene, available state-of-the-art semiconductor processes were used to create layers of aluminum gallium arsenide (AlGaAs) and GaAs that comprised a quantum well over which a hexagonal array of quantum dots was contained beneath nanopillars created in the top layer of the electron-confining structure. These hexagonal patterned GaAs structures—which behave like artificial atoms only 50 nm apart—allow quantum-mechanical interactions much like the electron-sharing behavior of atoms in a solid. The nanofabrication processes used enable engineering of novel structures that can be used to manipulate the flow of electrons and photons to mimic not only graphene’s myriad uses, but to define new structures with advanced capabilities still being imagined. Reference: S. Wang et al., Nature Nanotechnol., 13, 1, 29–33 (2018).