Controlled Growth of Vertically Aligned Nanocomposites through a Au Seeding-Assisted Method

Jianan Shen; Zedong Hu; Lizabeth Quigley; Haiyan Wang

doi:10.1021/acsomega.3c04701

Controlled Growth of Vertically Aligned Nanocomposites through a Au Seeding-Assisted Method

ACS Omega. 2023 Sep 25;8(40):37140-37146. doi: 10.1021/acsomega.3c04701. eCollection 2023 Oct 10.

Authors

Jianan Shen¹, Zedong Hu², Lizabeth Quigley¹, Haiyan Wang^{1

2}

Affiliations

¹ School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907, United States.
² Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, United States.

Abstract

Heteroepitaxial metal-oxide vertically aligned nanocomposites (VAN) have piqued significant interest due to their remarkable vertical interfacial coupling effects, strong structural and property anisotropy, and potential applications in magnetoelectrics, photocatalysts, and optical metamaterials. VANs present a unique pillar-in-matrix structure with uniform but rather random pillar distributions. Achieving a well-controlled pillar growth remains a major challenge in this field. Here, we use BaTiO₃ (BTO)-Au as a model VAN system to demonstrate the effects of Au seedings on achieving such pillar-growth control with enhanced ordering and morphology tuning. The Au seedings are introduced using an anodic aluminum oxide (AAO) template through pulsed laser deposition (PLD). TEM characterization reveals that the Au seedings result in straighter and more evenly distributed Au pillars in the BTO matrix compared to those without seeding, with the diameter of the Au seedings increasing with the number of pulses. Additionally, spectroscopic ellipsometry demonstrates distinct permittivity dispersion for all samples. This demonstration lays a foundation for future controlled and selective growth of VAN systems for on-chip integration.