Effects of Varying the Preparation Conditions on the Dielectric Constant of Mixed Metal Oxide Films Derived from Layered Double Hydroxide Precursor Films

Magnesium/aluminum layered double hydroxide (LDH) films have been prepared in situ by means of urea hydrolysis using aluminum metal as both the substrate and sole source of aluminum. Scanning electron microscopy (SEM) images showed that the LDH crystallites are almost perpendicular to the substrate and interlaced with each other forming a network of vacant pockets. The film showed outstanding mechanical strength and high adhesion with the substrate. After being calcined at 500 degrees C, MgAl mixed metal oxide (MMO) films were obtained which retained the morphology of the precursor films. The values of dielectric constant (k) of the MgAl-MMO films were measured and showed low values in the range 2.0-4.7 arising from the low density of the interlaced structure. The effect of varying the preparation conditions of the LDH precursor films on the microstructure and k-value of the corresponding MMO films was investigated by varying the metal ion concentration, crystallization time, and crystallization temperature. The MMO films became more compact with increasing metal ion concentration and crystallization time, which resulted in increased k-values.