Uniform, Fully Connected, High‐Quality Monocrystalline Freestanding Perovskite Oxide Films Fabricated from Recyclable Substrates

Abstract

AbstractReleasing epitaxial perovskite oxide films from their native oxide substrates produces high quality, 2D‐material‐like monocrystalline freestanding oxide membranes, as potential key components for the next‐generation electronic devices. Two major obstacles still limit their practical applications: macroscopic material defects (mainly cracks) that lowers uniformity and yield, and the high cost of the consumed oxide substrates. Here, a two‐step film transfer method and a substrate recycling method enable repetitive fabrication of millimeter‐scale, fully‐connected freestanding oxide films of various chemical compositions from the same substrates; arrays of capacitor and resistor devices based on these oxides transferred on silicon indicate high uniformity, low sample‐to‐sample variation, and satisfactory electrical connectivity. The two‐step transfer suppresses crack formation by avoiding buckling‐delamination‐type relaxation of epitaxial strain, and the key point to achieve substrate reuse is to remove the residual Al species bonded to the substrate surfaces. The mitigation of such long‐lasting issues in freestanding oxide fabrication techniques may eventually pave roads toward future industrial‐grade devices, as well as enabling many research opportunities in fundamental physics.