Second Harmonic Generation On Hydrothermal Grown Zno Nanowires And Colloidal Nanostructures Films

We report a non-linear optical study on ZnO nanowires grown on FTO substrate and spin-cast colloidal nanostructures (PbS and PbS-Au) based films for the first time. Zinc oxide (ZnO) nanowire was grown by hydrothermal method on pre-cleaned, seeded FTO substrates, placed facedown in the aqueous solution of zinc nitrate hydrate and HMTA (Hexamethylenetetramine) for a few hours. The diameters diameters, lengths and density of ZnO nanowires could be controlled by varying seeding concentration, growth temperature and growth time.
Non-linear optical measurement was done using a systems of mirrors M1, M2, M3 stable for the power densities up to 1.5 GW/cm2, the laser fundamental beam of Nd:YAG laser was frequency doubled by a-BiB3O6 second harmonic crystals. Second harmonic generation was observed on the ZnO-nanowire-grown substrates. It was also noted the SHG pattern showed same pattern as the ZnO nanowire growth pattern. The general origin of the observed effect is caused by local acentricity of the titled compounds. Further studies will be done on nanostructures based devices. Similar studies were also done on spin-cast films made of colloidal nanostructures such as PbS and PbS-Au nanoparticles. SHG was also observed in such films.