When 3:30 PM - 5:00 PM Oct 23, 2015
Where 1571 G. G. Brown Building
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The 2015 Van Vlack Lecture Series: Quantum Dot Formation on Nanowires


Peter W. Voorhees
Northwestern University

Quantum dots embedded within nanowires hold great promise in many quantum photonics applications. However, controlling the formation of these dots remains a challenge. Recently, GaAs nanowires have been used as substrates to create novel optoelectronic devices by growing an AlGaAs alloy shell on a GaAs nanowire. The deposition of the AlGaAs layer leads to the spontaneous formation of stripes of Al along certain crystallographic directions and quantum dots near the apex of the shell. A model has been developed for the motion of the faceted AlGaAs-vapor interfaces that accounts for capillarity, deposition, and surface diffusion. We find that for certain combinations of these effects, facets can be present during growth that are not present on the interfacial energy minimizing Wulff shape. These small facets can have a slowly time-dependent size that can lead to the formation of stripes and quantum dots. The effects of surface diffusion, deposition, and surface energy on the development of stripes of Al and quantum dots will be discussed.

 

The Van Vlack Lecture Series was established in honor of L. H. Van Vlack, to provide a distinguished lecture series from the outstanding leaders in the field of Materials Science and Engineering

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