June 22, 2011

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In a paper titled “Nanoscale Effects on Heterojunction Electron Gases in GaN/AlGaN Core/Shell Nanowires” published in Nano Letters, Sandia scientist Bryan M. Wong, and EFRC scientists François Léonard, Qiming Li, and George T. Wang, present a theoretical  and computational study of the electronic properties of core/shell nanowires.  They find that the nanometer size scales combined with the highly anisotropic cross-sections of these nanowires strongly influences the behavior of the electron distribution, leading to confinement at corners and polar faces, and transitions between core-centered and interface-confined electron gases.  More generally, their results indicate that electron gases in closed nanoscale systems are qualitatively different from their bulk counterparts.

Bulk semiconductor-semiconductor heterojunctions have been instrumental in enabling technological breakthroughs in electronics and optoelectronics, including for solid-state lighting. Such heterojunctions in core/shell nanowires have recently been proposed as a novel route for solid-state lighting technology.  In order to assess the potential of such systems, it is important to understand the fundamental electronic and optical properties of these core/shell nanowires.