Facile Chemical Route to Prepare Water Soluble Epitaxial Sr₃Al₂O₆ Sacrificial Layers for Free‐Standing Oxides

Abstract

Abstract The growth of epitaxial complex oxides has been essentially limited to specific substrates that can induce epitaxial growth and stand high temperature thermal treatments. These restrictions hinder the opportunity to manipulate and integrate such materials into new artificial heterostructures including the use of polymeric and silicon substrates and study emergent phenomena for novel applications. To tackle this bottleneck, herein, a facile chemical route to prepare water‐soluble epitaxial Sr 3 Al 2 O 6 thin films to be used as sacrificial layer for future free‐standing epitaxial complex oxide manipulation is described. Two solution processes are put forward based on metal nitrate and metalorganic precursors to prepare dense, homogeneous and epitaxial Sr 3 Al 2 O 6 thin films that can be easily etched by milli‐Q water. Moreover, as a proof of concept, a basic heterostructure consisting of Al 2 O 3 /Sr 3 Al 2 O 6 on SrTiO 3 is fabricated to subsequently exfoliate the Al 2 O 3 thin film and transfer it to a polymer substrate. This is a robust chemical and low‐cost methodology that could be adopted to prepare a wide variety of thin films to fabricate artificial heterostructures to go beyond the traditional electronic, spintronic, and energy storage and conversion devices.