Opportunities and Challenges of Complex Oxide Membranes
The growing demand for integrating functional oxides onto dissimilar substrates has driven extensive research into detaching functional thin films from their original substrates to form membranes, enabling vertical or back-end-of-the-line (BEOL)integration. These functional oxide membranes, while exhibiting intriguing properties under extreme strain or free from clamping effects, present challenges in synthesizing high-quality films. In this presentation, I will discuss the challenges involved in synthesizing three-dimensional (3D) perovskite nanomembranes and the innovative approaches our group has developed to overcome these obstacles. Utilizing hybrid molecular beam epitaxy (MBE) with a metal-organic precursor, titanium isopropoxide, we successfully grew epitaxial SrTiO3 (STO) and BaTiO3 (BTO)films directly on graphene layers that were transferred onto bulk STOsubstrates. These films were then exfoliated and transferred onto various other substrates. Additionally, I will showcase a sacrificial layer method that enables the creation of oxide membranes with a room-temperature dielectric constant of approximately 300. The talk will conclude with an exploration of the potential applications of 3D nanomembranes in materials physics and device engineering.