title: Large-area regular nanodomain patterning in He-irradiated lithium niobate crystals.
abstract: Large-area ferroelectric nanodomain patterns, which are desirable for nonlinear optical applications, were generated in previously He-implanted lithium niobate crystals by applying voltage pulses to the tip of a scanning force microscope. The individual nanodomains were found to be of uniform size, which depended only on the inter-domain spacing and the pulse amplitude. We explain this behavior by the electrostatic repulsion of poling-induced buried charges between adjacent domains. The domain patterns were imaged by piezoresponse force microscopy and investigated by domain-selective etching in conjunction with focused ion beam etching followed by scanning electron microscopy imaging. In order to optimize the He-irradiation parameters for easy and reliable nanodomain patterning a series of samples subjected to various irradiation fluences and energies was prepared. The different samples were characterized by investigating nanodomains generated with a wide range of pulse parameters (amplitude and duration). In addition, these experiments clarified the physical mechanism behind the facile poling measured in He-irradiated lithium niobate crystals: the damage caused by the energy loss that takes place via electronic excitations appears to act to stabilize the domains, whereas the nuclear-collision damage degrades the crystal quality, and thus impedes reliable nanodomain generation.
authors.affiliation: Center for Integrated Science and Technology, Columbia University, New York, NY 10027, USA. ao2199@columbia.edu
authors.forename: A
authors.initials: A
authors.lastname: Ofan
authors.forename: M
authors.initials: M
authors.lastname: Lilienblum
authors.forename: O
authors.initials: O
authors.lastname: Gaathon
authors.forename: A
authors.initials: A
authors.lastname: Sehrbrock
authors.forename: A
authors.initials: A
authors.lastname: Hoffmann
authors.forename: S
authors.initials: S
authors.lastname: Bakhru
authors.forename: H
authors.initials: H
authors.lastname: Bakhru
authors.forename: S
authors.initials: S
authors.lastname: Irsen
authors.forename: R M
authors.initials: RM
authors.lastname: Osgood
authors.forename: E
authors.initials: E
authors.lastname: Soergel