Synthesis and electrophoretic deposition of high-dielectric-constant SrTiO3 nanoparticles

We have investigated on the synthesis of SrTiO3 nanoparticles whose bulk exhibits dielectric constant of 300, and their colloidal dispersion. As a result, we successfully synthesized SrTiO3 nanoparticles with an average diameter of 134–485 nm measured by a scanning electron microscopic observation. The SrTiO3 nanoparticles with a negative charge (ζ = −25 to −31 mV) can be dispersed as colloidal nanoparticles in water, and the average diameter in the dispersion were 138–356 nm measured by a dynamic light scattering technique. The colloidal dispersion of SrTiO3 nanoparticles is promising for fabrication of low-voltage organic field-effect transistors (FETs) by a wet-processing fabrication. We have also successfully prepared SrTiO3 films with a thickness of 1–10 μm on n-doped silicon substrates by an electrophoretic deposition technique. The SrTiO3 films on the silicon substrates are likely used as dielectric gate insulator to low-voltage organic FETs after a sintering treatment.