Upcoming Events

Solution-Grown Silicon and Germanium Nanowires

January 30, 2013 4:00PM to 5:00PM
Presenter 
Brian A. Korgel, University of Texas at Austin
Location 
Building 440, Room A105-106
Type 
Colloquium
Series 
NST Nanoscience Colloquium
Refreshments will be available at 3:30 p.m.

Abstract:
Synthetic methodshave been developed for a wide variety of nanocrystal and nanowire materials. Among these materials, silicon (Si) and germanium (Ge) have been some of the most challenging to synthesize in solution, but now chemical methods now exist for producing significant quantities of colloidal Si and Ge nanocrystals, nanorods and nanowires. This presentation will provide examples of sterically-stabilized colloidal Si nanocrystals with narrow size distributions and good size control from 2 to >12 nm diameter and light emission that can be tuned to the bulk band edge of Si. It is now possible to form superlattices with Si nanocrystals by self-assembly.

Transmission electron microscopy of Si nanocrystals on graphene enables the direct visualization of organic capping ligands. Accurate size-dependent Raman spectroscopy data of Si nanocrystals without the influence of stress from an embedding matrix will also be presented and compared to model calculations. Some latest results on Si and Ge nanowires produced by solution-based methods in our group will also be presented. Non-woven fabric of Si and Ge nanowires can be formed with extremely high optical densities. Si and Ge nanowires can be combined with polymer and elastomeric hosts to create new semiconductor-based materials with unique combinations of optical, electronic and mechanical properties. And in high capacity lithium ion batteries, Si and Ge nanowire anodes can increase the storage capacity of the anode bymore than five times its current capacity