Insulator-to-semiconductor transition of nanocrystalline BaTiO3 at temperatures ≤200 °C

Abstract

As a classic dielectric material, BaTiO₃ is one of the most important materials used in electronic applications. In this work, highly dense BaTiO₃ ceramics with an average grain size of 35 nm were prepared, and dielectric and electrical properties were investigated. Microcrystalline BaTiO₃ is an insulator at low temperatures; however, nanocrystalline BaTiO₃ shows considerable semiconductivity with an activation energy of only 0.27 eV at temperatures ≤200 °C. At room temperature, the conductivity of nanocrystalline BaTiO₃ is about fourteen orders of magnitude higher than that of the microcrystalline counterpart. Only by decreasing the grain size, one can transform BaTiO₃ from an insulator to a semiconductor.