Kinetic Growth Regimes of Hydrothermally Synthesized Potassium Tantalate Nanoparticles

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.