Ferroelectric BiFeO3 nanodots formed in non-crystallized BiFeO3 thin-films via a local heating process using a heated atomic force microscope tip

A BiFeO 3 thin-film was prepared from a solution by deposition on a Pt/TiO 2 /SiO 2 /Si substrate via a spin coating process and was subsequently annealed at 300 °C for 1 h to afford a non-crystallized BiFeO 3 thin-film. Locally crystallized BiFeO 3 nanodots were formed in the non-crystallized BiFeO 3 thin-film via a local crystallization process using an atomic force microscope tip heated to 550 °C. By controlling the local heating time, ferroelectric BiFeO 3 nanodots with different diameters ranging from 65 to 120 nm were obtained. The ferroelectric properties of the BiFeO 3 nanodots were further investigated by studying the local ferroelectric switching behaviors and local piezoelectric d 33 hysteresis loops using a piezoresponse force microscope.