Effects of substrate etching, Sn~(+2) doping and surfactant addition on the morphology of chemically deposited zinc oxide films

摘要

The effect of substrate etching by HF, doping by SnCl2 and the addition of a surfactant such as Tiron on the morphology and growth rate of zinc oxide deposits is investigated. The layer is produced on a high purity alumina (HPA) substrate by two-stage chemical deposition (TSCD) from a solution containing an ammonium zinc complex. Etching does not affect the structure of films thinner than 400 nm. It has, however, a considerable effect on the structure of films greater than 800 nm. The latter is produced by 70 times dipping of the substrate into the ZnO containing solution. It is seen that 100 times of dipping results in the formation of acicular grains on the initially formed grains. The addition of 2 drops per lit (d/l) of Tiron changes the surface morphology and causes the formation of a fine-grained structure. Further addition of Tiron causes poisoning of the nucleation stage and coarsens the grains. The same effect is observed with Sn-doping of the film. Adding more than 2% Sn as a dopant induces poisoning of the nucleation stage and hinders the formation of fine grains. Combined substrate etching and Tiron addition effects are discussed in this paper.