Study of the morphology and luminescence of SnO2 micro- and nanostructures synthesized by a two step thermal process

A study of the variation of structural and optical properties of different SnO2 micro- and nanostructures grown by thermal treatments including a post-growth annealing under argon flow has been carried out. The samples have been characterized by atomic force microscopy (AFM) and cathodoluminescence (CL) in the scanning electron microscope (SEM). It has been found that a post-growth annealing under argon flow at high temperature modifies the appearance of the initial structures as well as their optical properties. In this way, micro- and nanoislands terraced features or microtubes with smooth surfaces have been obtained as a function of the crystallographic orientation of the initial structure used as a substrate. Some other effects such as the increase of the 1.94 eV CL emission, related to oxygen vacancies, which involves an electrical conductivity increase, are achieved by the annealing treatment.