Growth Time Effect on the Structural and Sub-structural Properties of Chemically-deposited ZnO films

摘要

Nanostructured ZnO films are obtained by chemical bath deposition from zinc nitrate, hexamethylenetetramine and ammonia. The evolution of the structural and sub-structural properties of the films is characterized using high resolution scanning electron microscopy (SEM) and X-ray diffraction analysis. In particular, we detail here the influence of condensation time on the crystal phase, texture quality, lattice constants, grain size, coherent scattering domain size (CSD), microstrain, stress and concentration of dislocations. Obtained condensates have the wurtzite structure with lattice parameters in the range a = 0.3248-0.3254 nm and c = 0.5206-0.5214 nm, depending on the condensation time. The grain size and microstrain in the direction perpendicular to the crystallographic planes (002) are in the range L ～ 26-42 nm and ε～(0.59-3.09)×10~(-3), respectively. Furthermore, the effects of deposition time on microstrain, stress and concentration of dislocations in the layers is established. By adjusting the condensation time, we are able to produce ZnO films with controlled structural properties: from nanorods to continuous nanostructured films.