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arXiv · 2307.14966

Super-tetragonal Sr4Al2O7: a versatile sacrificial layer for high-integrity freestanding oxide membranes

Jinfeng Zhang·Ting Lin·Ao Wang·Xiaochao Wang·Qingyu He·Huan Ye·Jingdi Lu·Qing Wang·Zhengguo Liang·Feng Jin·Shengru Chen·Minghui Fan·Er-Jia Guo·Qinghua Zhang·Lin Gu·Zhenlin Luo·Liang Si·Wenbin Wu·Lingfei Wang
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Abstract

Releasing the epitaxial oxide heterostructures from substrate constraints leads to the emergence of various correlated electronic phases and paves the way for integrations with advanced semiconductor technologies. Identifying a suitable water-soluble sacrificial layer, compatible with the high-quality epitaxial growth of oxide heterostructures, is currently the key to the development of large-scale freestanding oxide membranes. In this study, we unveil the super-tetragonal Sr4Al2O7 (SAOT) as a promising water-soluble sacrificial layer. The distinct low-symmetric crystal structure of SAOT enables a superior capability to sustain epitaxial strain, thus allowing for broad tunability in lattice constants. The resultant structural coherency and defect-free interface in perovskite ABO3/SAOT heterostructures effectively restrain crack formations during the water-assisted release of freestanding oxide membranes. For a variety of non-ferroelectric oxide membranes, the crack-free areas can span up to a few millimeters in length scale. These compelling features, combined with the inherent high-water solubility, make SAOT a versatile and feasible sacrificial layer for producing high-quality freestanding oxide membranes, thereby boosting their potential for innovative oxide electronics and flexible device designs.

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Jinfeng Zhang, Ting Lin, Ao Wang, Xiaochao Wang, Qingyu He, Huan Ye, Jingdi Lu, Qing Wang, Zhengguo Liang, Feng Jin, Shengru Chen, Minghui Fan, Er-Jia Guo, Qinghua Zhang, Lin Gu, Zhenlin Luo, Liang Si, Wenbin Wu, Lingfei Wang. 2023-07-27. Super-tetragonal Sr4Al2O7: a versatile sacrificial layer for high-integrity freestanding oxide membranes. https://arxiv.org/abs/2307.14966

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