Influence of the Precursors and Chemical Composition of the Solution on the Properties of ZnO Thin Films Grown by Spray Pyrolysis

The effect of the solution composition on the properties of ZnO thin films grown by spray pyrolysis has been investigated. The ZnO films, both undoped and doped with either magnesium or aluminum, have been grown employing different solvents and different precursor salts. Afterward the effects of these have been correlated to the morphology and optical and electrical properties of the films. In general it was found that organic salts are preferable over inorganic ones such as chlorides and nitrates. In the case of inorganic salts, unwanted etching processes, caused by acids formed as a result of the precursor decomposition, lead to degradation of the films performance. Similarly, organic solvents are preferable over water due to a better droplet size distribution and, also, due to additional heat transfer toward the sample surface by their burning.