Atomic Force Microscopy Observation of the Initial Growth Stage and the Ferroelectric Properties of Bi2VO5.5 Films on SrTiO3(100), Si(100) Substrates

Abstract

The initial growth mechanism of Bi2VO5.5 thin films on SrTiO3(100) has been studied using atomic force microscopy (AFM), and c-axis oriented ultra-thin films have been prepared by laser ablation. The Bi2VO5.5 films are constructed at various growth temperatures. The films deposited at 500° C grow by the step-flow mode, whereas the films deposited at 400° C grow by homogeneous nucleation. From these results, it is evident that Bi2VO5.5 grows in multiples of 0.8 nm as complete molecular units and that the top-most layer is Bi2O2. The dielectric constant of Bi2VO5.5 thin films formed on Si(100) is about 35, and a C-V plot of a Bi2VO5.5-SiO2 MIS capacitor subjected to dc polarizing voltages shows memory windows of 0.1 V against a ±2 V gate bias.