Effect of precursor solution concentration on the grain orientation of Bi_3.15Nd_0.85Ti₃O₁₂thin films

Abstract

Polycrystalline Bi3.15Nd0.85Ti3O12 (BNT) thin films were fabricated on Pt/Ti/SiO2/Si by the sol–gel method. The dependence of precursor solution concentration (PSC) on the grain orientation of the films was observed, and a model was proposed to explain it by taking into account the effect of bulk nucleation. With increasing PSC, the BNT thin film turned from c-axis-preferential-oriented to random-oriented. It is suggested that a competition exists between the nucleation and grain growth on the grain orientation. When the PSC is low, the former plays a predominant role, while in the opposite case, the latter is dominant. The bulk nucleation inhibits the homoepitaxial grain growth, and it gradually replaces the heterogeneous nucleation as the main nucleation mechanism with the increase in PSC.