Mapping Dopant Distribution in Semiconductor Nanowires

Lincoln Lauhon, Northwestern University, DMR-0449933

Semiconductor nanowires are promising materials for a range of nano-enabled applications in sensing, opto/electronics, and energy storage and conversion. Their properties are controlled by tuning the diameter, composition, and doping. We have developed a method to map the distribution of dopants within individual semiconductor nanowires, providing essential guidance to the design of improved growth processes and device models.

Atom Probe Tomography Reconstruction Top and side views of the Ge (green dots) and P (brown spheres) atom distributions in a phosphorous-doped germanium NW. The P concentration in the NW core is (10 ppm) is much less than the gas phase (700 ppm) and shell (1500 ppm).

Ge P

Side View

50 nm

Top View

14 n

m x

14

nm

Shell

Core

Engaging K-12 Teachers in Teaching and Research of Nanomaterials

Lincoln Lauhon, Northwestern University, DMR-0449933

A nanoscience concept inventory was developed to help 7-16 teachers align curricular goals with the needs of a future ‘nano’ literate workforce. Development has continued and accelerated through collaborations within the National Center for Learning and Teaching (NCLT) at Northwestern University. Nate Unterman, a high school teacher co-developing the inventory, presented results of an assessment instrument based on the inventory at the American Chemical Society meeting in Chicago. The effort now involves researchers at least 5 partner institutions.

Leveraging the RET ProgramLeveraging the NCLT Program

Prof. Lauhon directed the Research Experience for Teachers (RET) program since 2004. Sherri Rukes, a RET 2006 participant in Prof. Ken Shull’s group, was awarded a $10,000 grant from BP to develop a laboratory project on fuel cells.

Greg Swackhammer, Prof. Lauhon, and Sherri Rukes observe a super-absorbent polymer in action as part of a nanomaterials activity demonstration.