The use of quaternary ammonium bromides to control the microstructure of zinc oxide films formed using aerosol assisted chemical vapour deposition

A method in which the microstructure of thin films of zinc oxide can be controlled through the use of readily available additives is presented. This paper will discuss the use of a range of tetra-alkyl quaternary ammonium bromides as additives during the aerosol assisted chemical vapour deposition of zinc oxide, synthesised primarily from a solution of zinc acetate in methanol. Using a combination of single and dual source aerosol assisted chemical vapour deposition and analysis using scanning electron microscopy, we will present a range of morphologies, including plates with rough edges, plates with well-defined hexagonal structures, and organised stacks growing perpendicular to the substrate. Powder X-Ray diffraction techniques reveal that films grown in the presence of the additives also display high levels of preferred orientation when compared to zinc oxide films formed in the absence of any quaternary ammonium bromides. We will also demonstrate the influence of additives on the thickness of the films.