Two-Photon Photoluminescence from Hierarchical ZnO Nanostructures

G. GRINBLAT; M. TIRADO; D. COMEDI; M.G. CAPELUTO; A.V. BRAGAS

Encuentro; 221st Electrochemical Society Meeting; 2012

ZnO is a wide (3.3eV at room temperature), direct band gap semiconductor with a high exciton binding energy (60meV), hence a promising material for applications in opto-electronic devices, such as ultraviolet laser diodes, solar cells, ultrasensitive gas sensors and many others. Several physical and chemical techniques have been developed for the growth of different types of ZnO nanostructures, enabling many interesting devices based on this material. Nanolasers have been already fabricated, and solar cells are expected to be more efficient due to the higher specific area in a nanostructure. Due to the absence of centrosymmetry, nonlinear optical properties become important in ZnO. Second harmonic generation (SHG) and low lasing threshold through two-photon pumping have been reported for ZnO nanowires. In this work, we study the photoluminescence from hierarchical ZnO nanostructures (such as nanowires, nanocombs, nanosheets and nanohedgehogs) excited through two-photon absorption processes. The nanoobjects were grown through a vapor-phase transport technique in a tubular furnace. Silicon based substrates were used, over which Au nanoclusters were deposited as growth catalyzers.