Analysis and characterization of tin-doped ZnO nanostructures

Abstract

In this paper, undoped and tin-doped ZnO nanostructures were grown onto non-conductive substrates by a simple solution method. Structural, morphological, optical and electrical properties of the structures were investigated with respect to tin concentration. From XRD studies, all the ZnO nanostructures were found as hexagonal wurtzite type structures growing preponderantly oriented with c-axis nor- mal to the substrate. An increase in tin content resulted in a decrease in grain size, whereas the dislocation density in- creases. SEM observations indicated that all the structures were textured throughout the substrates without any cracks or pores. The influence of incorporation of tin on surface morphology of the samples was clearly seen. Average diameter of the nanostructures decreased with increasing tin content. Absorption spectra of the structures revealed that the band gap of the films increases with increasing tin concentration. It is found that the tin-doped samples have higher average transmittance than the undoped one. The 1 % tin-doped sample exhibited ∼80 % average transparency, which was the best transparency among the doped samples. Electrical measurements showed that resistivity of the structures increased with increasing dopant concentration. This increasing was attributed due to a decrease in carrier con- centration caused by carrier traps at the grain boundaries.