Science and Engineering

Howard University

Tito Huber, Pratibha Dev, Thomas Searles
Washington, DC
December 2017


Researchers at Howard University seek to develop an understanding of science at the interfaces of quantum materials such as two-dimensional (2D) quantum layers and nanostructured semimetals.  These structures stretch the boundaries of nanotechnology to the atomic domain and have dramatic new properties at room temperature that promise to transform optoelectronics.  Quantum size-effects such as transitions from a semi-metallic state to topologically non-trivial states have been observed in semimetals such as bismuth.  The role played by these emergent quantum phenomena on the properties of the interfaces of such structures remains unknown and are ripe for exploration.  As a proof-of-principle, the researchers will study semimetal thin films/nanowire arrays that are capped by a 2D layered material such as graphene.  The capping layer will provide: (i) the means to effect charge-separation at the interfaces, and (ii) a path for charge transport.  The interfacial properties are expected to be modified by the quantum confinement effects, surface effects, and defects within the semimetal and the capping layer.  Employing a wide range of experimental techniques, the team will study these effects on photogeneration and charge-separation at the interfaces of these structures.  This project will leverage unique materials growth and characterization facilities at Howard University, including: high-pressure, high-temperature growth of semimetal nanowire arrays; scanning electron microscopy; and, Raman microscopy.  State-of-the-art computational methods based on density functional theory will be used to explain and guide the experimental efforts.  The proposed research will answer fundamental questions about novel low-dimensional materials and will impact future optoelectronics and quantum technologies.

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