Optical properties of single-crystalline ZnO nanowires on m-sapphire

ZnO nanowires have been synthesized using a catalyst-assisted heteroepitaxial carbothermal reduction approach on a m-sapphire substrate. Intricate and uniform arrays have been obtained with each nanowire forming an angle similar to30degrees with the substrate normal. Photoluminescence studies at room temperature for wavelengths between 335 and 620 nm reveal a strong single exciton peak at similar to380 nm (3.26 eV) with accompanying deep-level blueshifted emission peaks at similar to486, 490, and 510 nm. UV resonant Raman spectroscopy has been used to characterize the nanowires at room temperature with multiphonon scattering exhibiting phonon quantum confinement. (C) 2003 American Institute of Physics.