Self-Organized Epitaxial Vertically Aligned Nanocomposites with Long-Range Ordering Enabled by Substrate Nanotemplating.

Abstract

Vertically aligned nanocomposites (VAN) thin films present as an intriguing material family for achieving novel functionalities. However, most of the VAN structures tend to grow in a random fashion, hindering the future integration in nanoscale devices. Previous efforts for achieving ordered nanopillar structures have been focused on specific systems, and rely on sophisticated lithography and seeding techniques, making large area ordering quite difficult. In this work, a new technique is presented to produce self-assembled nanocomposites with long-range ordering through selective nucleation of nanocomposites on termination patterned substrates. Specifically, SrTiO₃ (001) substrates have been annealed to achieve alternating chemical terminations and thus enable selective epitaxy during the VAN growth. La_0.7 Sr_0.3 MnO₃ :CeO₂ (LSMO):CeO₂ nanocomposites, as a prototype, are demonstrated to form well-ordered rows in matrix structure, with CeO₂ (011) domains selectively grown on SrO terminated area, showing enhanced functionality. This approach provides a large degree of long-range ordering for nanocomposite growth that could lead to unique functionalities and takes the nanocomposites one step closer toward future nanoscale device integration.