Porous yttria-stabilized zirconia (YSZ) thin films were prepared by pulsed laser deposition to investigate the influence of specific surface area on the electrical and protonic transport properties.

Monophasic nano-crystalline CoFe 2 O 4 (CFO) nanoparticles of high purity have been synthesised through a low temperature hydrothermal route, which does not involve hazardous chemicals, or conditions. The easy, green procedure involves a hydrothermal treatment at 135 C of an aqueous suspension of the oxalate salts of the precursors. No further purification or annealing procedure was necessary to obtain the crystalline nano-structured oxide. The nanoparticles were characterized structurally and chemically by powder X-ray diffraction (PXRD), Inductively Coupled Plasma Spectrometry (ICP-MS) and Scanning Electron Microscopy (SEM), thus confirming the successful synthesis of the CoFe 2 O 4 particles with the expected crystal phase and stoichiometry and an almost complete inverse spinel structure. From the nanoparticles pellets were pressed to investigate the electronic conduction properties using electrochemical impedance spectroscopy (EIS). At low temperatures, the conductivity measurements reveal a semiconducting behavior originating from hopping between Co sites and a total conductivity dominated by the grain boundary contribution. At higher temperatures (T > 400 C) a metallic-insulator transition occurs, which is attributed to additional hopping of electrons between the Fe sites.

Area-selective atomic layer deposition is a key technology for modern microelectronics as it eliminates alignment errors inherent to conventional approaches by enabling material deposition only in specific areas. Typically, the selectivity originates from surface modifications of the substrate that allow or block precursor adsorption. The control of the deposition process currently remains a major challenge as the selectivity of the no-growth areas is lost quickly. Here, we show that surface modifications of the substrate strongly manipulate the surface diffusion. The selective deposition of TiO2 on poly (methyl methacrylate) and SiO2 yields localized nanostructures with tailored aspect ratios. Controlling the surface diffusion allows to tune such nanostructures as it boosts the growth rate at the interface of the growth and no-growth areas. Kinetic Monte-Carlo calculations reveal that species move from high to low diffusion areas. Further, we identify the catalytic activity of TiCl4 during the formation of carboxylic acid on poly (methyl methacrylate) as the reaction mechanism responsible for the loss of selectivity, and show that process optimization leads to higher selectivity. Our work enables the precise control of areaselective atomic layer deposition on the nanoscale, and offers new strategies in area-selective deposition processes by exploiting surface diffusion effects.