It is known that in sol–gel method, water and acid amounts affect the hydrolysis and condensation reaction rates;
whereas solvent amount and temperature affect the particle size and crystal structure of the synthesized powder.
Powders possessing desired properties can be synthesized by altering these parameters. The synthesis conditions and
designations employed in the present study are presented in Table 1. XRD patterns of the aluminum doped ZnO powder synthesized through hydrothermal method in various conditions are presented in Fig. 1. The AZO-1 powder has a completely amorphous structure. AZO-2 powder was obtained by changing only the water amount. It can be
seen from the XRD pattern of AZO-2 that the powder is composed of slightly crystalline hexagonal Zn(OH)2 (PDF
#12-0142) and orthorhombic Al2(OOH)2 (PDF #05-190) structures. In the experiments designated as AZO-3 and
AZO-4, the prepared sols were mixed for 19 h, prior to heating in the autoclave. The mixing duration, given in
Table 1 is the time that the sols were mixed on a magnetic stirrer, before heating and reacting in the autoclave.