Zinc diketonates as single source precursors for ZnO nanoparticles: microwave-assisted synthesis, electrophoretic deposition and field-effect transistor device properties

Abstract

The microwave-assisted decomposition of zinc diketonates in acetonitrile leads to stable dispersions of zinc oxide nanoparticles. The variation of the diketonato ligand framework permits controlling the size of primary crystallites and soft agglomerates, which allows the synthesis of nanoparticles in the range of 4–6 nm. Field-effect transistors are fabricated with charge carrier mobility as high as 0.32 cm² V⁻¹ s⁻¹ and an I_on/off ratio of ∼10⁶ after post-annealing at only 250 °C in air. Their superior performance is attributed to the dense packing of the ZnO particles in the semiconducting layer. Dispersions in aprotic solvent are suitable for a cathodic electrophoretic deposition of ZnO layers on ITO coated glass electrodes. Uniform ZnO coatings exhibiting interference colours can be obtained with thicknesses of several hundred nanometers.