Kinetic Growth Regimes of Hydrothermally Synthesized Potassium Tantalate Nanoparticles.

Abstract

A general mathematical kinetic growth model is proposed on the basis of observed growth regimes of hydrothermally synthesized KTaO₃ nanoparticles from electron microscopy studies on the surface morphology and surface chemistry. Secondary electron imaging demonstrated that there are two dominant growth mechanisms: terrace nucleation, where the surfaces are rough, and terrace growth, where surfaces are smooth. In the proposed model based upon standard step-flow growth, the rates of both mechanisms are established to be dependent on the chemical potential change of the growth environment-terrace nucleation dominates with larger negative chemical potential, and terrace growth dominates with smaller negative chemical potential. This analysis illustrates the importance of ending a synthesis in a regime of low negative chemical potential in order to achieve smooth well-faceted nanoparticles.