Nonlinear imaging and spectroscopy of ZnO nanostructures

PHYS 415

Ralph L. House, rlhouse@email.unc.edu, Brian Mehl, Abhineet Uppal, Chuan Zhang, Amanda Reams, and John M. Papanikolas, john_papanikolas@unc.edu. Department of Chemistry, CB#3290, University of North Carolina, Rm# 123 Caudill Labs, Chapel Hill, NC 27599
The recently realized potential of ZnO in nanostructured devices and optoelectronics, due in part to its wide band gap (3.37 eV) and large exciton-binding energy (60 meV), has led to extensive research to synthesize and characterize various nanostructures. Steady state emission of the relative amplitudes between band-edge (390 nm) and trap emission (550 nm; arising due to defects within a crystal) is often used as a benchmark of crystal quality. However, these measurements represent an ensemble average, making it impossible to discern the variation between each structure. Using hydrothermal synthetic methods we have synthesized several ZnO nanostructures. By combining two-photon and second harmonic generation microscopy, as well as fluorescence lifetime imaging, we have characterized the heterogeneity within an ensemble by comparing emission spectra between single nanostructures. Furthermore, we have shown that the spectra depend on the location they are collected, indicating an inherent heterogeneity present within each structure.
 

PHYS Poster Session - Nanostructured Materials and Nanophotonics
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A, Poster

Sci-Mix
8:00 PM-10:00 PM, Monday, April 7, 2008 Morial Convention Center -- Hall A, Sci-Mix

Division of Physical Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008