Researchers have long been seeking multifunctional materials that can be adopted for next-generation nanoelectronics, and which, hopefully, are compatible with current semiconductor processing for further integration. Along this vein, complex oxides have gained numerous attention due to their versatile functionalities. Despite the fact that unbounded potential of complex oxides has been examined over the past years, one of the major challenges lies in the direct integration of these functional oxides onto existing devices or targeted substrates that are inherently incompatible in terms of oxide growth. To fulfill this goal, freestanding processes have been proposed, in which wet etching of inserted sacrificial layers is regarded as one of the most efficient ways to obtain epitaxial high-quality thin films. In this study, we propose using an alternative oxide, YBa₂Cu₃O₇ (YCBO), as a sacrificial layer, which can be easily dissolved in light hydrochloric acid in a more efficient way, while protecting selected complex oxides intact. The high epitaxial quality of the selected complex oxide before and after freestanding process using YBCO as a sacrificial layer is comprehensively studied via a combination of atomic force microscopy, X-ray diffraction, transmission electron microscopy, and electrical transports. This approach enables direct integration of complex oxides with arbitrary substrates and devices and is expected to offer a faster route towards the development of low-dimensional quantum materials.

长期以来，研究人员一直在寻找可用于下一代纳米电子技术的多功能材料，希望该材料与当前的半导体工艺兼容，以进行进一步的集成。沿着这种脉络，复杂的氧化物由于其多功能的功能性而受到了广泛的关注。尽管在过去的几年中已经检查了复合氧化物的无限潜力，但主要挑战之一是将这些功能性氧化物直接整合到现有设备或目标衬底上，而这些设备在氧化物生长方面固有地不兼容。为了实现该目标，已经提出了独立的工艺，其中，将插入的牺牲层的湿法蚀刻视为获得外延高质量薄膜的最有效方法之一。在这个研究中，₂ Cu ₃ O ₇（YCBO），作为牺牲层，可以更有效地轻松溶解在轻质盐酸中，同时完整保护选定的复合氧化物。通过原子力显微镜，X射线衍射，透射电子显微镜和电传输的综合研究，综合研究了使用YBCO作为牺牲层的独立工艺前后所选复合氧化物的高外延质量。这种方法可以使复杂的氧化物与任意衬底和器件直接集成，并有望为开发低维量子材料提供更快的途径。