Polyoxoniobates as molecular building blocks in thin films

Niobium oxide thin films have been prepared by spin-coating aqueous solutions of tetramethylammonium salts of the isostructural polyoxometalate clusters [Nb10O28](6-), [TiNb9O28](7-) and [Ti2Nb8O28](8-) onto silicon wafers, and annealing them. The [Nb10O28](6-) cluster yields films of Nb2O5 in the orthorhombic and monoclinic crystal phases when annealed at 800 degrees C and 1000 degrees C, respectively, whereas the [TiNb9O28](7-) and [Ti2Nb8O28](8-) clusters yield the monoclinic crystal phases of Ti2Nb12O29 and TiNb2O7 (titanium-niobium oxides) in different ratios. We also demonstrate a protocol for depositing successive layers of metal oxide films. Finally, we explore factors affecting the roughness of the films.

Automated summary

Niobium oxide thin films were prepared by spin-coating aqueous solutions of tetramethylammonium salts of isostructural polyoxometalate clusters onto silicon wafers and annealing them, resulting in different crystal phases. A protocol for depositing successive layers of metal oxide films was demonstrated, and factors affecting the roughness of the films were explored.