title: Controllable growth of ultrathin BiFeO3 from finger-like nanostripes to atomically flat films.
abstract: BiFeO3 (BFO) ultrathin films with nominal thicknesses from 2 to 12 nm were grown with a SrRuO3 (SRO) buffer layer on TiO2-terminated (001) SrTiO3 (STO) substrates using pulsed laser deposition. The surface morphologies and domain configurations of the thin films were investigated using atomic force microscopy and piezoelectric force microscopy. Periodical one-dimensional finger-like nanostripes of BFO on the SRO covered STO substrates were observed. With increasing thickness, the BFO ultrathin films develop from the finger-like nanostripes to an atomically flat surface. The formation of the finger-like nanostructures of BFO is related to the atomic step or terrace structure of the substrate. The BFO nanostripes and the atomically flat thin films both show good ferroelectricity. The as-grown domain orientations of the BFO ultrathin films are ascribed to the chemical terminations at the surface of the SRO layer. These results indicate that the surface morphologies and the domain configurations of BFO ultrathin films can be artificially designed by using substrates with optimized terrace structures and chemical termination, and these films are potentially useful in multifunctional nanoelectronic devices.
authors.affiliation: Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Feng
authors.forename: Can
authors.initials: C
authors.lastname: Wang
authors.forename: Shilu
authors.initials: S
authors.lastname: Tian
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhou
authors.forename: Chen
authors.initials: C
authors.lastname: Ge
authors.forename: Haizhong
authors.initials: H
authors.lastname: Guo
authors.forename: Meng
authors.initials: M
authors.lastname: He
authors.forename: Kuijuan
authors.initials: K
authors.lastname: Jin
authors.forename: Guozhen
authors.initials: G
authors.lastname: Yang