  We have characterized the growth of ZnO using sequential infiltration
synthesis (SiS) on PS-b-PMMA block copolymers (BCP) of spherical and
cylindrical sub-20nm morphologies and studied how the photoluminescence of
these nanostructures varies per its seed layer. Investigation of these
structures was done using atomic force microscopy (AFM), spectrofluorometry,
Raman spectroscopy, and scanning electron microscopy (SEM). We report
blue-shifted photoemission at 335 nm (3.70 eV), suggesting quantum confinement
effects. This UV-photoluminescence can be translated into emitter sizes of
roughly 1.5nm in radius. Furthermore, samples of ZnO prepared with an alumina
seed layer showed additional defect state photoemission at 470 nm and 520 nm
for spherical and cylindrical BCP morphologies, respectively. Defect
photoemission was not observed in samples prepared without a seed layer. Raman
and EXAFS data suggest lack of long range order between the ZnO nanostructures
during early stages of infiltrated ZnO growth and therefore supports the blue
shift emission is due to confinement. Our work demonstrates that ZnO
nanostructures grown on PS-b-PMMA via infiltration are advantageous in
uniformity and size, and exhibit unique fluorescence properties. These
observations suggest that infiltrated ZnO in PS-b-PMMA nanostructures lends
itself to a new regime of applications in photonics and quantum materials.
