Lee Dong Kyu, Park Yunkyu, Sim Hyeji, Park Jinheon, Kim Younghak, Kim Gi-Yeop, Eom Chang-Beom, Choi Si-Young, Son Junwoo
Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, Republic of Korea.
Pohang Accelerator Laboratory, Pohang, Republic of Korea.
Nat Commun. 2021 Aug 18;12(1):5019. doi: 10.1038/s41467-021-24740-2.
Unrestricted integration of single-crystal oxide films on arbitrary substrates has been of great interest to exploit emerging phenomena from transition metal oxides for practical applications. Here, we demonstrate the release and transfer of a freestanding single-crystalline rutile oxide nanomembranes to serve as an epitaxial template for heterogeneous integration of correlated oxides on dissimilar substrates. By selective oxidation and dissolution of sacrificial VO buffer layers from TiO/VO/TiO by HO, millimeter-size TiO single-crystalline layers are integrated on silicon without any deterioration. After subsequent VO epitaxial growth on the transferred TiO nanomembranes, we create artificial single-crystalline oxide/Si heterostructures with excellent sharpness of metal-insulator transition ([Formula: see text] > 10) even in ultrathin (<10 nm) VO films that are not achievable via direct growth on Si. This discovery offers a synthetic strategy to release the new single-crystalline oxide nanomembranes and an integration scheme to exploit emergent functionality from epitaxial oxide heterostructures in mature silicon devices.
在任意衬底上无限制地集成单晶氧化物薄膜，对于利用过渡金属氧化物中出现的新现象以实现实际应用具有重大意义。在此，我们展示了独立的单晶金红石氧化物纳米膜的释放和转移，以作为在不同衬底上异质集成相关氧化物的外延模板。通过用HO对TiO/VO/TiO中的牺牲VO缓冲层进行选择性氧化和溶解，毫米尺寸的TiO单晶层被集成到硅上而没有任何退化。在转移的TiO纳米膜上随后进行VO外延生长后，我们创建了人工单晶氧化物/硅异质结构，即使在超薄（<10nm）的VO薄膜中，其金属 - 绝缘体转变的锐度也非常出色（[公式：见原文] > 10），而这是通过在硅上直接生长无法实现的。这一发现提供了一种释放新型单晶氧化物纳米膜的合成策略，以及一种在成熟硅器件中利用外延氧化物异质结构的新兴功能的集成方案。
