Grain texture dependent charge transport behaviors and dielectric responses of BaTiO3 films fabricated on MgO substrates

Abstract

For many technological applications, it is necessary to grow films on substrates with large lattice mismatches or even substrates having a completely different crystalline structure. Here, barium titanate (BaTiO3) films were fabricated on SrRuO3 (SRO)-buffered MgO(001), (110), and (111) substrates using RF magnetron sputtering. Unlike the BaTiO3 film grown on SRO-buffered MgO(001) substrate that exhibited pure (001) grain orientation, a dominant (110)-oriented grain texture with traces of (111)-oriented grains was identified in the BaTiO3 films grown on SRO-buffered MgO(110) and (111) substrates. The different texture characteristics were verified through Raman scattering. In particular, the characteristics and mechanism of charge transport and dielectric responses of these films were studied and they were observed to exhibit significantly different leakage-current behavior. The distinct differences in the electrical properties of the above texture-engineered BaTiO3 films were predominantly attributed to the different polarization states (the tilting angle, the inversion domains) caused by their different grain texture characteristics.