Recycling of Perovskite Substrate

TL;DR

This paper demonstrates a method to recycle costly SrTiO3 substrates after producing freestanding perovskite thin films, maintaining their structural and electrical properties through simple hot water treatment.

Contribution

It introduces a practical recycling process for SrTiO3 substrates used in perovskite thin film fabrication, reducing costs and waste.

Findings

SrTiO3 substrates can be effectively recycled after film fabrication.

Hot water soaking restores substrate surface to original structure.

Recycled substrates produce films with nearly identical properties.

Abstract

The use of water-soluble sacrificial layer of Sr$_3$Al$_2$O$_6$ has tremendously boosted the research on freestanding functional oxide thin films, especially thanks to its ultimate capability to produce high-quality epitaxial perovskite thin films. However, the costly single-crystalline substrates, e.g. SrTiO$_3$, were generally discarded after obtaining the freestanding thin films. Here, we demonstrate that the SrTiO$_3$ substrates can be recycled to fabricate La$_{0.7}$Sr$_{0.3}$MnO$_3$ films with nearly identical structural and electrical properties. After attaining freestanding thin films, the residues on SrTiO$_3$ can be removed by 80 \degree C hot water soaking and rinsing treatments. Consequently, the surface of SrTiO$_3$ reverted to its original step-and-terrace structure.