Effects of annealing temperature on morphologies and optical properties of ZnO nanostructures

The effects of annealing temperature on the morphologies and optical properties of ZnO nanostructures synthesized by sol–gel method were investigated in detail. The SEM results showed that uniform ZnO nanorods formed at 900 ∘C. The PL results showed an ultraviolet emission peak and a relatively broad visible light emission peak for all ZnO nanostructures sintered at different temperature. The increase of the crystal size and decrease of tensile stress resulted in the UV emission peak shifted from 386 to 389 nm when annealing temperature rose from 850 to 1000 ∘C. The growth mechanism of the ZnO nanorods is discussed.