Effect of substrate on the preferred orientation of ZnO films by chemical solution deposition

ZnO films were fabricated on different substrates using chemical solution deposition. Zinc acetate, 2-methoxyethanol, and diethanolamine were used for the synthesis of the precursor solutions. Three types of substrates such as (1 1 1)-oriented Pt, (2 0 0)-oriented Pt, and amorphous silicon nitride on silicon wafers were used. Strong dependence of the preferred orientation on substrate was characterized. The degree of c-axis orientation of solution-derived ZnO films is greatly enhanced by using the substrate with smaller lattice mismatch. Grain growth is also promoted on such substrates. The preferred orientation and microstructure of ZnO films by chemical solution deposition are discussed in terms of the change in driving force for crystallization due to the accompanying variations that occur in the energy barrier heights for nucleation on the surface of substrates.