Maintaining The Structural Integrity of Wet-Transferred Graphene to Achieve Successful Exfoliation of BTO in Heterostructures Grown through Pulsed Laser Deposition (PLD)

The epitaxial growth of functional oxides on graphene-coated substrates presents a promising avenue for producing self-standing epitaxial nanomembranes, thereby facilitating advanced scientific investigations, applications, and sustainable substrate reutilization. However, the conventional use of aggressive oxidizing conditions in the growth of epitaxial oxides can jeopardize the integrity of the graphene layer. This study introduces a systematic approach to safeguard graphene during the epitaxial growth of BaTiO3 (BTO) on SrTiO3 (STO) substrates coated with graphene. Our method involves an initial BTO growth phase using a laser source with a controlled aperture, thereby adjusting the growth rate to minimize damage to the underlying graphene layer. Additionally, a precisely regulated chemical vapor deposition (CVD) process is employed to grow graphene with larger grain sizes, thereby enhancing the crystalline quality of the remotely epitaxially grown BTO film. Gradual strain relaxation is observed in the resulting BTO films upon the incorporation of multiple graphene layers. The use of bilayer graphene facilitates the easy exfoliation and transfer of the BTO film to various substrates, including Si. These findings pave the way for the heterogeneous integration of different functional oxides, holding significant implications for the commercialization of perovskite oxides in flexible electronics.