Formation of ferroelectric multi-domains and electrical conduction in epitaxial BiFeO3 nanodots fabricated with AAO nanotemplates

The electrical conduction property of ferroelectric domains formed in nanoscale dots is an important issue for miniaturized non-volatile random access memory applications. Herein, the conduction characteristics of ferroelectric domain structures formed in epitaxial BiFeO3 (BFO) nanodots are evaluated. Nanoscale BFO dots are fabricated on Nb-doped SrTiO3 (Nb:STO) substrates using an anodic aluminum oxide (AAO) nanotemplate, spin-coating, and etching processes. Using various sizes, such as 65 nm, 50 nm, and 35 nm, of the BFO nanodots, the domain wall current and the current that is dependent on the direction of polarization are measured. A piezoresponse force microscope study reveals that multiple ferroelectric domains coexist in one BFO nanodot. A large current is measured using a conducting atomic force microscope at the domain wall location in the ferroelectric domains. After ferroelectric polarization switching of the domains, the current is slightly dependent on the polarization direction. The electrical resistance state is dependent on the presence or absence of domain walls within the ferroelectric domains of the BFO nanodots.