Re: Reminder: PhD defense - Irene Goldthorpe

Mani,

I was going to pick up my nephew at the airport, but just got a VM
saying they are stuck for the night in Toronto.
So not yet sure what is going on.

I might swing by the gym and perhaps even climb. When are you going to
be there?

Andreas

On Aug 11, 2009, at 3:11 PM, Irene Goldthorpe wrote:

> SYNTHESIS AND CHARACTERIZATION OF GERMANIUM NANOWIRES AND GERMANIUM/
> SILICON RADIALLY HETEROSTRUCTURED NANOWIRES
>
> Irene Goldthorpe
> Department of Materials Science and Engineering
> Advisor: Prof. Paul McIntyre
>
> Thursday, August 13th, 10:00 am (refreshments at 9:45 am)
> Location: McCullough 115
>
> ABSTRACT:
>
> Because semiconductor nanowires possess a variety of technologically
> useful properties and can be synthesized with relative ease, they
> are attractive candidates for a wide range of electronic, optical,
> sensing, and energy applications. The first part of this talk will
> focus on germanium nanowires, because of germanium's compatibility
> with standard integrated circuit fabrication processes, its high
> electron and hole mobilities, and the low temperature required for
> germanium nanowire growth. The chemical vapor deposition of
> epitaxially-aligned germanium nanowires with uniform diameters
> between 5 and 50 nm will be discussed. Next, I will demonstrate the
> synthesis of a radial heterostructure, where silicon is
> heteroepitaxially deposited around a germanium nanowire. This
> silicon shell passivates the germanium nanowire surface, creates an
> electronic band offset to confine holes away the surface where they
> can scatter or recombine, and induces strain which could allow for
> the engineering of properties such as carrier mobilities and band
> gap. Detailed transmission electron microscopy and x-ray
> diffraction characterization of various Ge-core/Si-shell nanowire
> samples show that, analogous to planar heteroepitaxy, surface
> roughening and misfit dislocations relax misfit strain. Lessons
> learned generated strategies to avoid the strain-induced surface
> roughening that promotes dislocation nucleation, resulting in the
> fabrication of metastably strained, dislocation-free core-shell
> nanowires.

---
Andreas Goebel
cell 408-464-2790