The exploration of crystalline nanostructures offers a promising avenue for understanding quantum phenomena and developing innovative materials. This research introduces a novel approach to fabricating high-quality nanocrystalline oxide structures through a self-assembly process. By dewetting ultrathin oxide membranes transferred onto sapphire substrates, the process yields nanovoids, nanowires, and nanocrystals in a sequential manner. The resulting nanostructures exhibit exceptional anisotropy, high crystallinity, and uniform stoichiometry, driven by the minimization of interfacial energy along specific crystallographic directions. This self-assembly technique provides a versatile platform for investigating surface diffusion phenomena and advancing epitaxial growth technologies. The precise control over nanostructure orientation, size, and morphology opens up exciting possibilities for applications in optics, catalysis, and nanoelectronics. Moreover, these nanostructures offer a unique opportunity to study fundamental properties and effects related to finite size, interfaces, and space charge layers. The universality of the dewetting process suggests its potential for broader application in nanostructuring various functional materials. Advanced atomic-resolution scanning transmission electron microscopy and electron energy-loss spectroscopy corroborate these findings.

Details can be found at V. Harbola, Y. Wu, H. Wang, S. Smink, S. Parks, P. A. van Aken, J. Mannhart. Self-Assembly of Nanocrystalline Structures from Freestanding Oxide Membranes. Adv. Mater. 2023, 2210989. https://onlinelibrary.wiley.com/doi/10.1002/adma.202210989.